Sunday, January 26, 2020

Gestalt and Holistic Treatment (Principle of Totality)

Gestalt and Holistic Treatment (Principle of Totality) 1. What Is Holistic Psychology? Holism talks about any way that stresses the entire psychic thinking reasonably than their fundamental elements. Conversely knows as ‘the entire is larger than the sum of its parts’. A holistic method consequently recommends that there are diverse stages of explanation and that at every stage there exist â€Å"emergent characteristics† that cannot be condensed. (McLeod, 2008) 2. Holistic psychology:  A New Science Holistic psychology constructs on anything that has gone before. Alike Gestalt psychology, it claims the honor in full. Along with Psych combination and transpersonal psychology, it openly talks about the inspirational and the mystical elements. It knocks varied causes to accept, acclimate, and elaborate methods, including them into its practice of individual alteration, adaptation, and therapeutic. Although it’s not new yet is innovative and different in every part, as holistic psychology offers in full a new start. It strips away covered ideas from the preceding that are incorrect and restraining, and plugs in fundamentally new guidelines. Thus it’s a practice for discovering and converting perception which leads us to a new empire within. (Bà ¶dy, 2009) 3. General talk on Holistic Psychology Approaches Dr Lisa MatthewmanC Psychol AFBPsS . Registered Professional Psychologist, (AFBPsS, 2009) discovers the use of holistic psychology with distinct clients and analyzes the modern holistic methods to structural happiness. ‘Holistic’ or ‘integrative’ thinking is the education and repetition of how to return to our usual entirety. It is a combined method that talks on psychological wellness via linking and endorsing the fitness of the physique and soul, while incorporating customary psychological treatments. It highlights the interdependence of physical, psychic and mental dynamics. Studying ‘completeness and well. being’ from a organizations viewpoint it syndicates advanced psychological knowledge with customary healing insights and paradigms from harmonizing therapy (AFBPsS, 2009) 4. History of Gestalt psychology Gestalt theory originated nearly in 19th century in Austria and south Germany as a protest in contradiction of structural universities fractional study of understanding intoatomisticessentials. Max Wertheimer,Wolfgang Kohlerand Kurt Koffka worked together to found Gestalt. Gestalt psychologyof the Berlin School is a philosophy of observance and intelligence speculating that the functioning norm of the mind is holistic, corresponding, and equivalent, with self. organizing propensities. (Liquori, 2011). While numerous modern psychologists reserve that even these propensities are the result of information and education, all approve that they are robust and almost universal tendencies. (John M. Darley, (1991).) 5. Principle of Totality The philosophy of Gestalt psychology is grounded on the principle of totality: The principle of totality which is a straightforward theoretic belief of gestalt theory, affirming that mindful knowledge should be watched holistically, as an entirety of the active communications of constituents of the brain. (Concepts, 2015) ThePrinciple of Totality—the conscious experience must be measured internationally by captivating into interpretation all the bodily and psychological characteristics of the individual at the same time because the environment of the mind stresses that all constituents be measured as portion of an arrangement of dynamic relationships. The norm supports that the human eye perceives matters in their whole before observing their separate parts†¦ that the whole is diverse than the sum of its parts. These are our â€Å"psychological shortcuts† for obtaining and upholding steady percepts in our loud world. We want these shortcuts to curtail policymaking time and permit us to function without continually stopping to contemplate about the subsequent course of action. (Tyne, 2013) 6. Perception of Apparent Motion – Causes of Wertheimers Innovation that launched the Gestalt Revolution Max Wertheimer (1880. 1943), the creator of the Gestalt School of Psychology, printed a critique mono. graph on the perception of apparent motion in 1912, which started a new way for a great contract of succeeding perceptual viewpoint and examination. Wertheimers examination was stimulated by an unexpected scrutiny of a pure ostensible effort, which he called the phi. phenomenon to differentiate it from best apparent movement (beta), which looks a lot like real movement. Wertheimer named his original comments pure since it was professed in the absence of any thing being understood to modify its spot in universe. The phi. phenomenon, as well as the finest circumstances for seeing it, were not defined evidently in this monograph, foremost substantial following confusion aroused about its appearance and incidence. We appraise the antiquity leading to the detection of the phi. phenomenon, and then define: (i) A probable basis for the misperception obvious in most modern investigation on the phi. phenomenon; (ii) The finest circumstances for perceiving the phi. phenomenon; (iii) new circumstances that provide a mainly bright phi. phenomenon; and (iv) two outlines of thought that may deliver clarifications of the phi. phenomenon and also differentiate phi from beta. (Steinman RM1, 2015) 7. Gestalt principles of form perception their application in Modern Era Gestalt psychology tries to comprehend mental phenomena by inspecting them as prearranged and designed rather than the amount of their essential parts. Thus, Gestalt psychology distances itself from the extra decomposition. al methods to thinking like structuralism with its inclination to examine psychological actions into basic feelings and it highlights on ideas like developing properties, holism, and context. (Soegaard., 2014) Nowadays, businesses have understood these principles and deeply encompassed them into their advertising. Gestalt values keep the symbols stimulating and are inclined to catch people’s attention. Here I will discover many of the values and find real life instances of advertising applications that apply to each gestalt principles. Figure and Ground: Individuals often rift pictorial info into character and ground. Figure is what views out, while ground is the background. This influence is utilized in one of the Macintosh logos. As you perceive below, the sign can be observed as an even happy expression and as a joyful face in profile observing at a processor screen. Proximity: When individual see incomes that are near enough together, they repeatedly notice the resources as a group. In 2002 the MTV European Music Prizes used an advertisement that documented the law of proximity. We notice the 2 symbols in the greater left as a group and the symbols of the supporters in the lowest right as a collection. The white space and the proximity of the symbols specify that the symbols are destined to be groups, without MTV demanding to recognize it. Closure: Individuals tend to complete things that are actually unfinished by filling in gaps. The IBM symbol is categorically only blue lines of various length, but we identify the letters I, B, and M. Similarity: Individuals are often inclined to cluster alike items together. The business Lega. Lega used this belief in their website design. They used the orange shade for all the signs at the upper right of the webpage so that individuals assemble the images together. Symmetry: When we notice things we have a tendency to to notice them as symmetrical shapes that form around their center. When we see two separated items that are symmetrical, we automatically see them as one item. Since the Us are proportioned to one another, we mechanically group each U with the one it is following to, leaving us with four objects rather than eight. (larwa002, 2011) 8. Contribution of the Field to Contemporary World: Some of the most notable contributions of Gestalt psychology to the understanding of humanperceptionand cognition include: The motion picture and animation industries (which began with studies on apparent motion); The three Gestalt organizing principles (i.e., figure. ground, grouping byproximity and similarity, and good continuation), which determine how our perceptions are organized; Koffkaà ¢Ã¢â€š ¬Ã… ¸s distinction between physical reality (the geographical environment; the world asit is) and perceived reality (behavioral environment; the world as we perceive it) Kà ¶hlerà ¢Ã¢â€š ¬Ã… ¸s isomorphism, the idea that perceptual experience (phenomenal reality) and the underlying physical reality (the physiological eventsof the nervous system) are functionally equivalent (â€Å"brain activity is isomorphic tophenomenological experience†); Kà ¶hlerà ¢Ã¢â€š ¬Ã… ¸s research on insight,(a sudden problem solution that occurs when an individual reorganizes the elements of a problem situation into a new configuration), which introduced a new way of thinking into the debate about learning and problem. solving and extended animal methodology beyond puzzle boxes and mazes; Wertheimer’s productivethinking, which wentbeyond therote learning and rule memorization used by thecontemporary educational system, in stating that productive thinking was a â€Å"true understanding† (of a problem) derived from a complete restructuring of the problem inorder to gain insight into itssolution; 9. Conclusion Though Gestalt thinking failed to develop as a main power in American mainstream thinkingit imparted as a robust customof accepting intricacy through examination into American psychology (Goodwin, 2008).It has had a deep influence on the method we comprehend socialperception and reasoning today.Not merely did it effect Pavlov’s trained response investigation and Maslow’s hierarchy of needs, the impact of Gestalt psychology can be seen through contemporary psychology in related psychological philosophies (i.e., Bronfenbrenner and Vygotsky),in contemporary communal psychology, in inspiration and goal. directedperformance, in trainingson prejudgment and its decrease, in. group devotion, andthe efficiencyof groupprocedures (Lewis); in trainings onprevention and its denigrating effect on behavior (regression), in modern developmental psychology, and in modern cognitive psychology, which investigates such topics as the organizationà ¢Ã¢â€š ¬Ã… ¸ of information in memory (Goo dwin, 2008).According to Ralph White(as cited in Goodwin, 2008), it â€Å"is very much alive† in the â€Å"form of paying continual attention to the patterns of motivation and cognition that directly determine behavior, in the form of a selective but fairly 10. References AFBPsS, D. L. (2009). Registered Occupational Psychologist and International Society for Coaching Psychology. Bà ¶dy, D. G. (2009). http://holisticrenewal.com/holistic. psychology/what. is. holistic. psychology.html. Retrieved from http://holisticrenewal.com/holistic. psychology/what. is. holistic. psychology.html Concepts, P. (2015). Psychology Concepts. Retrieved from http://www.psychologyconcepts.com/principle. of. totality/ John M. Darley, S. G. ((1991).). Psychology,. Engelwood Cliffs, NJ: Fifth Edition, Prentice. Hall. larwa002. (2011, october 9). Effective Use of Gestalt Principles. Retrieved from http://blog.lib.umn.edu/: http://blog.lib.umn.edu/clar0841/psychblog/2011/10/effective. use. of. gestalt. principles.html Liquori, E. (2011). The Close Relationship Between Gestalt Principles and Design. Retrieved from http://www.instantshift.com/: http://www.instantshift.com/2011/09/19/the. close. relationship. between. gestalt. principles. and. design/ McLeod, S. (2008). Reductionism and Holism. Retrieved from http://www.simplypsychology.org/reductionism. holism.html Soegaard., M. (2014). Gestalt principles of form perception. Retrieved from https://www.interaction. design.org: https://www.interaction. design.org/encyclopedia/gestalt_principles_of_form_perception.html Steinman RM1, P. Z. (2015). Phi is not beta, and why Wertheimers discovery launched the Gestalt revolution. http://www.ncbi.nlm.nih.gov/pubmed/10927113. Tyne, S. V. (2013, September 8). The Whole is Other Than the Sum of the Parts: Principles of Gestalt Perception. Retrieved from http://seanvantyne.com/: http://seanvantyne.com/wordpress/2013/09/08/the. whole. is. other. than. the. sum. of. the. parts. principles. of. gestalt. perception/comment. page. 1/ Goodwin, C. J. (2008). A history of modern psychology (3rd ed.). Hoboken, NJ/ Wiley Sons.

Saturday, January 18, 2020

Thermodynamic Analysis and Performance Characteristics

AEROSPACE ENGINEERING SCHOOL OF MECHANICAL ENGINEERING AND DESIGN THE THERMODYNAMIC ANALYSIS AND PERFORMANCE CHARACTRISTICS OF A TURBOFAN JET ENGINE By J. E, Ibok 2011 Supervisor: Dr Lionel Ganippa ABSTRACT This work focuses on the performance analysis of a twin spool mixed flow turbofan engine. The main objective was to investigate the effects of using hydrogen, kerosene and natural gas fuel on the performance characteristics such as net thrust, specific fuel consumption and propulsive efficiency of the turbofan.Another aim of this work was to introduce the concept of exergy and thermoeconomics analysis for twin spool mixed flow turbofan engine and show the components that contributes the most to the inefficiency of the engine. A generic simulation was carried out using Gas Turb 11 software to obtain reasonable analysis results that were verified with a real-time JT8D-15A turbofan engine. The parametric analysis was done for constant value of mass flow rate of fuel and constant turb ine inlet temperature for all three fuels.The result were rightfully obtained for these analysis cases and discussed accordingly. Brunel University Mechanical Engineering Academic Session: 2010/2011 Name of Student: Johnson Essien Ibok Supervisor:Dr Lionel Ganippa Title: The Performance Characteristics and Thermodynamics Exergy and Thermoeconomics analysis of a Twin Spool Mixed Flow Turbofan Engine Operating at 30,000ft at M0 0. using Kerosene, natural Gas and Hydrogen Fuel. Abstract: This work focuses on the performance analysis of a twin spool mixed flow turbofan engine. A generic simulation was carried out using Gas Turb 11 software to obtain reasonable analysis results that were verified with a real-time JT8D-15A turbofan engine. The parametric analysis was done for constant value of mass flow rate of fuel and constant turbine inlet temperature for all three fuels.The result were rightfully obtained for these analysis cases and discussed accordingly. Objectives: The main aim of this work is to conduct the parametric cycle simulation of a twin spool mixed flow turbofan engine and investigate the performance characteristics of it. Another aim of this work is to show the effects of using hydrogen, Kerosene and natural gas fuel on the overall performance of the twin spool mixed flow turbofan engine.Also, the purpose of this work is to introduce the use of the second law of thermodynamics analysis known as exergy and thermoeconomics in analysis the twin spool mixed flow turbofan engine Background/Applications: This work is applicable in so many ways when it comes to the overall performance optimization and feasibility analysis of a jet engine. This work relates to the aerospace and aviation industries since the turbofan engine is amongst the vast number of jet engine used in propulsion of aircrafts.There is increasing pressure in the aviation industry to reduce pollution and depletion of energy resources while at the same time maintaining reasonable investment cost and high overall performance. Hence, this research was conducted in hopes of coming up with a new solution to this problem. Conclusions: The main conclusion drawn from the performance analysis is that hydrogen fuel produced the highest thrust level and the lowest specific fuel consumption between the three fuels for a constant mass flow rate of fuel.Kerosene fuel generated thrust level can be increased if it is mixed with a small amount of hydrogen. The Exit jet velocity ratio remained constant despite the increasing bypass ratio for all three fuels at constant mass flow rate of fuel. Using the exergetic analysis showed that the combustion chamber and the mixer contributed the most to the inefficiency of the turbofan engine. The amount of exergy transferred into the turbofan engine by hydrogen was depleted in the smallest ratio compared to natural gas and kerosene for constant mass flow rate of fuel.The thermoeconomics analysis showed that it is preferable to use local based co st evaluation to quantity specific thermoeconomics cost of thrust than the global method since the value was lower. Results: The results obtained from the simulation using Gas Turb 11 produced an error range of 0. 25% – 8. 5% when verified with the actual test data of the JT8D-15A turbofan engine. The results obtained for the analysis defined a reference design point at which the parametric analysis was conducted on. The analysis was done in three cases as shown clearly in the test matrix in table 1 below.Analysis| Parameters being varied| Parameters Kept Constant| Performance Characteristics| case 1| * Bypass ratio * Turbine Inlet temperature| * HPC Pressure Ratio * LPC Pressure Ratio * Fan Pressure Ratio| * Velocity ratio * Fuel-Air-ratio * Turbine inlet temperature * Net thrust * Specific Fuel Consumption * Thermal efficiency * Propulsive efficiency| case 2| * Bypass Ratio * Three different fuelsmH2mCH4mC12H23| * Mass flow rate of fuel * HPC Pressure Ratio * LPC Pressure R atio * Fan Pressure Ratio| | Case 3| * Bypass Ratio * Three different fuelsmH2mCH4mC12H23| * Turbine inlet temperature * HPC Pressure Ratio * LPC Pressure Ratio * Fan Pressure Ratio| | Table 1 The Test matrix of the Parametric Analysis. The exergy analysis was done for the parametric analysis of case 2 and case 3 where the exergy destruction rates, exergetic efficiency, exergy improvement potential rate and fuel depletion ratio were calculated. The distribution of these results throughout each component of the turbofan engine was represented with bar charts and Grassmann diagram. The thermoeconomics analysis was conducted for analysis case 2 using kerosene fuel.The specific thermoeconomics cost of thrust was calculated using global and local based cost evaluation methods. ACKNOWLEDGEMENTS First of all, I would like to thank my parents for their financial support and encouragement because without them I would not be here and be able to do this work. I am deeply thankful to my supervi sor, Dr Lionel Ganippa for believing in me and giving me the opportunity to work with him in this field of study. I am also thankful to him for giving the necessary guidance and advice and his enthusiasm and innovative ideas inspired me. Finally, I would like to thank Mr Joachim Kurzke for providing me with the necessary software needed for my dissertation. Table of ContentsAcknowledgements i Contents ii List of Notations and Subscripts iv List of Tables vi List of Figures vi Chapter 1: Introduction1 1. 1. Aims and Objectives2 1. 2. Computational Modeling3 Chapter 2: Jet Engines4 2. 1. Performance characteristics4 2. 1. 1. Thrust4 2. 1. 2. Thermal Efficiency5 2. 1. 3. Propulsive efficiency5 2. 1. 4. Overall efficiency6 2. 1. 5. Specific Fuel Consumption6 2. 2. Fuel and Propellants For Jet Engines7 Chapter 3: Turbofan Jet Engines †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ †¦8 3. 1. Introduction 8 3. 2. Classification of Turbofan Engines9 3. 3. Major Components of a Turbofan Engine10 3. 3. 1. Diffuser10 3. 3. 2. Fan and Compressor11 3. 3. 3. Combustion Chamber12 3. 3. 4. Turbine13 3. 3. 5. Exhaust Nozzle14 3. 4.Thermodynamic Process and Cycle of a Twin Spool Mixed Flow Turbofan Engine15 Chapter 4: Mathematical and Gas turb 11 Modeling of the turbofan Engine18 4. 1. Station Numbering and Assumptions18 4. 2. Design Point Cycle Simulation of the Turbofan Engine18 4. 3. Off-design Point Cycle Simulation of the Turbofan Engine21 4. 3. 1. Module/Component Matching 22 4. 3. 2. Off-Design Point Component Modeling22 Chapter 5: Methodology, Results and Discussions26 5. 1. General Relationship equations of the Major Parameters27 5. 2. Results and Discussions of Parametric cycle Analysis of Case 129 5. 3. Results and Discussions of Parametric Cycle Analysis of Case 235 5. 4.Results and Discussions of Parametric Cycle Analysis of Case 343 Chap ter 6: Exergy and Thermoeconomics Analysis of the Turbofan Engine49 6. 1. Exergy Analysis49 6. 1. 1. Exergy Analysis Modeling 50 6. 1. 2. Exergy and Energy Balance Equations of the Components58 6. 1. 3. General Relationships in Exergetic Analysis of the Turbofan Engine60 6. 1. 4. Results and Discussions61 6. 1. 5. Grassmann Diagram72 6. 2. Thermoeconomics Analysis74 6. 2. 1. Thermoeconomics Analysis Modelling74 6. 2. 2. Global Based Cost Evaluation76 6. 2. 3. Local Based Cost Evaluation77 6. 2. 4. Results and Discussion of the Thermoeconomics Analysis78 Chapter 7 Conclusions and Future Work80 Reference Appendix A Exergy Analysis Results Appendix B Thermoeconomics Analysis resultsList of Notations and Units ?| Isentropic efficiency| ?| Total Pressure ratio| m| Mass Flow Rate (kg/s)| f| Fuel/Air Ratio| M| Mach Number| Pt| Total pressure (kPa)| Tt| Total Temperature (K)| NCV| Net Calorific Value (MJ/kg)| Ht| Total Enthalpy (kJ/kg)| V| Velocity (m/s)| ?| Bypass Ratio| T| Static Temperat ure (K)| P| Static Pressure (kPa)| N| Actual Spool Speed (RPM)| Nc| Corrected Spool Speed (RPM)| mc| Corrected Mass Flow Rate (kg/s)| R| Universal Gas Constant (kJ/kmolK)| ?0| Standard Chemical Exergy (kJ/kmol)| Ex| Exergy Rate (MW)| xi| Mole Fraction| cp| Specific Heat at Constant Pressure (kJ/kgK)| ?| Ratio of Chemical Exergy to NCV| ?| Exergetic Efficiency| | Fuel Depletion Ratio| W| Power Rate of Work done (MW)| List of Subscripts| | LPT| Low Pressure Turbine| HPT| High Pressure Turbine| CC| Combustion Chamber| HPC| High Pressure Compressor| LPC| Low Pressure Compressor| d| Diffuser| noz| Nozzle| mix| Mixer| dest| Destruction Rate| 0, ambFAR| Ambient conditionFuel-Air-Ratio| CH| Chemical| PH| Physical| KN| Kinetic| PN| Potential| IP| Exergy Improvement Potential Rate (MW)| CRF| Cost Recovery Factor| c| Specific Thermoeconomic Cost (MJ/kg)| STD| Standard Temperature and Pressure| TIT| Turbine Inlet Temperature| TSFC| Thrust Specific Fuel Consumption (g/kNs)| SFC| Specific Fuel Co nsumption| p| Propulsive| TH| Thermal|O| Overall| T| Thrust| equip| Equipment| PEC| Capital Cost of Equipment| List of Tables Table 1 input parameters for Design Point Cycle Simulation on Gas Turb 1119 Table 2 Comparison table for the Actual Test Data and Simulated Data using gas Turb 1121 Table 3 Comparison Table for Actual Test Data and Simulated Off-Design Point data Using gas Turb 11. 25 Table 4 Equivalence Ratio of the three Fuels Combustion Processes†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 62 Table 5 Assumed Capital costs of Each Component of the Turbofan Engine. 75 Table 6 Flow of Specific Thermoeconomics Cost in all the Components 79 List of Figures Figure 1 Classification of Turbofan Engine9Figure 2 Layout of Forward Fan Twin Spool Mixed Flow Turbofan16 Figure 3 T-S Diagram for the Forward Fan Twin Spool Mixed Flow Turbofan17 Figure 4 Design Point Cycle Simulation Algorithm Using Gas Turb 1120 Figure 5 Example of a Compressor Performance Map/Cu rve24 Figure 6 Effects of Varying Bypass Ratio at Constant Values of TIT on Fuel-Air-Ratio30 Figure 7 Effects of Varying Bypass Ratio at Constant Values of TIT on Exit Velocity Ratio30 Figure 8 Effects of Varying Bypass Ratio at Constant Values of TIT on LPT Exit Pressure Ratio31 Figure 9 Effects of Varying Bypass Ratio at Constant Values of TIT on Net Thrust32 Figure 10 Effects of Varying Bypass Ratio at Constant Values of TIT on Specific Fuel Consumption33 Figure 11 Effects of Varying Bypass Ratio at Constant Values of TIT on Propulsive Efficiency34 Figure 12 Effects of Varying Bypass Ratio t Constant Values of TIT on Thermal Efficiency35 Figure 13 T-S diagram of using Hydrogen Fuel when the bypass Ratio is increased36 Figure 14 Variation of Fuel-Air-Ratio with Bypass Ratio at Constant Fuel Flow Rate using three different Fuels37 Figure 15 Variation of TIT with Bypass Ratio at Constant Fuel Flow Rate using three different Fuels37 Figure 16 Variation of Exit Velocity Ratio with Byp ass Ratio at Constant Fuel Flow Rate using three different Fuels38 Figure 17 Variation of LPT Exit Pressure Ratio with Bypass Ratio at Constant Fuel Flow Rate using three different Fuels39 Figure 18 Variation of Net Thrust with Bypass Ratio at Constant Fuel Flow Rate using three different Fuels40 Figure 19 Variation of Specific Fuel Consumption with Bypass Ratio at Constant Fuel Flow Rate using three different Fuels41 Figure 20 Variation of Thermal Efficiency with Bypass Ratio at Constant Fuel Flow Rate using three different Fuels42 Figure 21 Variation of Propulsive Efficiency with Bypass Ratio at Constant Fuel Flow Rate using three different Fuels43 Figure 22 Variation of Fuel-Air-Ratio with Bypass Ratio at Constant TIT using the three Different Fuels44 Figure 23 Variation of Exit Velocity Ratio with Bypass Ratio at Constant TIT using the three Different Fuels44 Figure 24 Variation of LPT Exit Pressure Ratio with Bypass Ratio at Constant TIT using the three Different Fuels45 Figure 25 Variation of Net Thrust with Bypass Ratio at Constant TIT using the three Different Fuels46 Figure 26 Variation of Specific Fuel Consumption with Bypass Ratio at Constant TIT using the three Different Fuels46 Figure 27 Variation of Propulsive Efficiency with Bypass Ratio at Constant TIT using the three Different Fuels47 Figure 28 Variation of Thermal Efficiency with Bypass Ratio at Constant TIT using the three Different Fuels48 Figure 29 Variation of Exergy Destruction Rate Using the three Fuels for Analysis Case 262 Figure 30 Variation of Exergy Destruction Rate Using the three Fuels for Analysis Case 364 Figure 31 Variation of Exergetic Efficiencies Using the three Fuels for Analysis Case 266 Figure 32 Variation of Exergetic Efficiencies Using the three Fuels for Analysis Case 367 Figure 33 Distribution of Exergy Improvement potential Rate Using the three Fuels for Analysis Case 268 Figure 34 Distribution of Exergy Improvement potential Rate Using the three Fuels for Analysis Case 369 Figure 35 variation of Fuel Depletion ratio using the Three Fuels for Analysis Case 270 Figure 36 variation of Fuel Depletion ratio using the Three Fuels for Analysis Case 371 Figure 37 Grassmann Diagram for the Exergetic analysis of Case 2 using kerosene Fuel for the Turbofan engine. 72 Chapter 1 Introduction Jet engines are complex thermodynamic systems that use a series of non-linear equation to define their thermodynamic processes and they operate under the principle of Brayton cycle.Brayton cycle is a cycle that comprises of the compressor, combustor and turbine working as a unit. Additionally, the major parameters that dictate the operational conditions of the engine at any point during the process are the relative altitude and Mach number. Mach number is the ratio of the velocity of the jet engine to the speed of sound. Basically, the main purpose of this type of thermodynamic system in aerospace industry is to accelerate a jet of air and as a result, generate enough thrust needed for flight. In addition, the design of jet engines is dependent of what purpose it will be used for in order to derive its maximum performance.For instance, in military application, jet engines are required to generate maximum thrust in minimum response time which consumes a lot of fuel whereas commercial jet engines are required to less noise generative, less fuel consuming and at the same time have high overall efficiency (El-sayed, 2008). There are certain factors that jet engine manufacturers take into consideration when designing jet engines which are the operating cost, engine noise, environmental emissions, fuel burn and overall efficiency. Accordingly, this has caused a global market competition for engine manufacturers like Rolls Royce, Pratt and Whitney, General Electric and CFM on who can produce the most efficient jet engines.In fact, Pratt and Whitney Company is working on a geared turbofan jet engine that they believe will reduce fuel burn, produce lesse r noise and emit less toxics while General Electric is coming up with simpler â€Å"ecore† jet engines that will be more fuel efficient than the current jet engines with as much as almost two fifths of current jet engines (Cassidy, 2008). Taking all that has been said into consideration, it can easily be asserted that by reducing the fuel consumption of the jet engine, the total temperature at the turbine blades will reduce thereby increasing the operating life and overall efficiency of the engine. Also, the total cost of the engine can be cut down. Indeed, Dr Pallan cited in (Ward, 2007) stated that reducing the fuel consumption by as little as 1% is highly longed after by engine manufacturers and this can result in very significant increase in the overall performance.In a general point of view, it can be said that the maximum point of achievement for jet engine manufacturers would be to design an engine that consumes the minimum amount of work in the compressor unit while g enerating the maximum amount of work in the turbine unit at minimum fuel supply. The main purpose of this work is to analyse the thermodynamic processes and performance of a jet engine using a simulation tool, exergy and thermoeconomics concept. 1. 1. Aims and Objectives The main objective of this work is to carry out the thermodynamic analysis and show the performance characteristics of a turbofan jet engine. In this work, the vivid explanation of the thermodynamics processes and cycle of each component of the turbofan engine starting from the diffuser to the nozzle will be covered. Also, the first and second law of thermodynamics with other laws will be applied extensively throughout this work.However, in the aspect of performance characteristics of the turbofan engine, a generic simulation will be carried out on a twin spool mixed flow turbofan engine. To relate this work to real life application, a JT8D-15A turbofan engine manufactured by Pratt and Whitney Company will be used a s the twin spool mixed flow turbofan for the simulation using the original design data. Indeed, the simulation tool that will be used is GasTurb 11 which was designed by Joachim Kurke and for more details on how it works can be found in (Kurke, 2007). This work will use the reference design point of the twin spool mixed flow turbofan at sea level with maximum take-off thrust to obtain the operating point of 30,000ft at M0 0. using the off-design performance simulation which will serve as the operating design point for the analysis in this work since the engine will spend most of its time in the cruise phase between 30000ft to 38000ft. The purpose of carrying this generic simulation of the turbofan engine is to investigate the effects of varying bypass ratio and turbine inlet temperature (thermal limit parameter) on the performance characteristics of the turbofan engine. In other words, the parametric cycle studies of the turbofan engine. This investigation will be done for three dif ferent cases which case 1 will be studying the effects of varying bypass ratio and turbine inlet temperature on the performance characteristics of the turbofan engine when some of the design choices are kept constant.The second case of study will be the comparison of the performance characteristics of the turbofan engine when three different fuels (kerosene, natural gas and Hydrogen) are used at the same mass flow rate using the same design point in case 1. Finally, the third case of study will be the comparison of the performance characteristics of the turbofan engine when the three fuels are undergoing the same combustion process that is constant turbine inlet temperature for the design point in case 1. This aspect of this analysis is very important owing to the growing problem of greenhouse effect and depletion of energy resources. In fact, statistics by the intergovernmental panel shows that aerospace industry is amongst one of the fast growing sources of greenhouse effect and t hat the emission of carbon dioxide will increase to five times what it is presently which is 3% (Symonds, 2005).Based on this, using alternative fuels like hydrogen and natural gas can tend to reduce pollution and consumption of energy resources risk and this work aims to show how that can be achieved while the overall efficiency of the engine is still high. Another approach of analysis in this work will be the use of the second law of thermodynamics analysis also known as exergy and thermoeconomics. This aspect of analysis of the turbofan engine will be done for the parametric analysis of case 2 and case 3 in efforts to also compare the three fuels that are being considered and show which fuel will cause the turbofan engine components to be most inefficient or have the most irreversibility.This analysis will be done by calculating the exergy relationships such as exergy transfer rates, exergy destruction rates, exergetic efficiencies, exergy improvement potential rates, and fuel de pletion ratios. Furthermore, the exergy analysis will be represented in a Grassmann diagram for parametric analysis case 2 of study. However, as for the thermoeconomics analysis of the turbofan engine, only parametric analysis case 3 studies will be done for only kerosene fuel and this work will aim to show how to use concept of local and global evaluation of thermoeconomic cost. 1. 2. Computational Modelling It will be very expensive and time wasting to design and develop new aircraft engine whenever an optimization or analysis wants to be done.In fact, Caoa Y, Jin, Meng and Fletcher (2005) stated that new ways should be developed to reduce aircraft engine design, maintenance and manufacturing cost in order to have effective worldwide market competition. Surprisingly, computer modelling is one approach of reducing manufacturing cost and time wasting. Computational modelling can simply be defined as the use of computer codes to replicate a typical system using some of its original d ata in order to analyse the system at varying conditions. The other side of the medallion shows simulation. There are many types of simulation tools normally used in simulating gas turbines such as Matlab/simulink, Modelica, Gas Turb 11, NPSS and many more. However, the simulation tool that will be adopted for the purpose of this dissertation is Gas Turb 11 designed by Joachim Kurzke.Gas Turb 11 is a language oriented program with a command prompt that calculates the output data without using block diagrams or graphical interface. It is user friendly in a sense that it is easy to find the tools library and to substitute data in for simulation. The Gas Turb 11 is specifically designed for simulation of all kinds of gas turbines starting from power generators to jet engines. Gas Turb 11 usually carries out two types of analysis which are the on design cycle point simulation and off-design cycle point simulation. Engine design point cycle simulation involves the study of comparing gas turbines of different geometry. This cycle design point must be defined before any other simulation can be done.On the other hand, off-design performance cycle point simulation involves the study of the behaviour of a gas turbine with known geometry. This cycle outlines the performance characteristics of each component such as performance maps, Overall efficiency. The type of simulation that will be done in this dissertation will involve the off-design and design point cycle. Chapter 2 Jet Engines 2. 1. Performance Parameter of Jet Engines 2. 2. 1. Thrust Thrust is the way of quantifying the ability of a jet engine to effectively utilise the energy added to it in order to propel or push itself forward in the opposite direction of the exiting jet in the exhaust nozzle.In other words, it is the reactive force to the force imparted by the exiting jet in the nozzle in accordance to Isaac Newton’s third law of motion. It is the most important parameter that has to be obtained for any jet engine and it depends heavily on the ingested mass of air, exiting velocity and pressure, the area of the nozzle, the flight velocity and ambient conditions. In fact, the mathematical expression for thrust which incorporates these factors is shown below as. Thrust=meVe-m0V0+Pe-P0Ae Where, e=the exit conditions at the exhaust nozzle, 0=ambient conditions at the inlet me=m0+mfuel Momentum Thrust=meVe; This is the thrust obtained from the reaction of the hot exhaust gases high velocity.Momentum Drag= m0V0 ; This the friction or drag force caused by the high velocity ingestion of air mass at the inlet. Pressure Thrust=Pe-P0Ae; This force is generated as a result of the higher exit static pressure compared to the ambient pressure which pushes back at the engine. Gross Thrust=meVe+Pe-P0Ae; It is the maximum obtainable positive thrust a jet engine can have when the drag forces are ignored. Special Cases of Thrust Take-off Thrust It is the thrust a jet engine can generate with its o wn power at static or low power setting which means the momentum drag component of thrust is ignored and the power of the engine at this point is equivalent to zero.This can be used to explain why the thrust of an engine at take-off condition is usually higher than at cruise condition since there is no momentum drag and effects of varying ambient condition. This only applies to turbojet, turbofan, and turboprop jet engines but when it comes to ramjet and scramjet, the air flow has to be accelerated by a booster system before it can start producing a positive take-off thrust. Pressure Thrust Component This is the thrust generated as a result of the static pressures of the exiting jet and ambient environment. In ideal cases where the nozzle has perfectly expanded the jet exit pressure to that of the ambient condition, the pressure thrust component will disappear which this case is not possible in reality.However, if the nozzle is choked which indicates that the ambient pressure is low er than the exit pressure of the jet, the pressure thrust component will have a positive effect on the net thrust. Also, if the nozzle tends to over expand the jet because of low energy addition to the jet and the exit pressure is lower than the ambient pressure, the pressure thrust component will have a negative effect on net thrust. 2. 2. 2. Thermal efficiency It is simply the measure at which energy in the engine system is converted. In other words, it is the measure at which total energy supplied to the engine system as heat transfer is converted to kinetic energy.In another way, it can easily be said to be the ratio of the power generated in the engine airflow to the rate at which energy is supplied in the fuel. ?TH=Power Generated in the Engine AirflowRate of Energy Supplied in the Fuel =12? meVe2-12? m0V02mfuel? NCV 2. 2. 3. Propulsive efficiency It is a measure at which kinetic energy possessed by air as it passes through the engine is converted into power of the propulsion of the engine. In mathematical terms, it is simply known as the ratio of thrust power to the power generated in the engine airflow. ?p=Thrust PowerPower Generated in the Engine Airflow = T? V012? meVe2-12? m0V02 2. 2. 4. Overall EfficiencyAs the name overall depicts, it is the resultant efficiency of a jet engine can have which is simply the product of the thermal and propulsive efficiencies. In mathematical terms, it is represented as shown below. ?O=? TH p =12? meVe2-12? m0V02mfuel? NCV? T? V012? meVe2-12? m0V02 =T? V0mfuel? NCV 2. 2. 5. Specific Fuel Consumption Specific fuel consumption as any other performance characteristics is a ratio and surprisingly it has a major effect on the economics of the aircraft as it is used to determine the aircrafts flight ticket costs. Specific fuel consumption has different expressions depending on what type of jet engine it is. For instance, in ramjet, turbojet and turbofan jet engines, it is the measure of the fuel mass flow rate to the thrus t force generated.Also, it is sometimes called the thrust specific fuel consumption (TSFC). TSFC=mfT However, in turbopropeller jet engines, it is the ratio of the fuel mass flow rate to the power generated in the engine shaft by the turbomachinery. It is sometimes referred to as the brake-specific fuel consumption (BSFC). TFSC=mfSP 2. 2. Fuel and Propellants for Jet Engines Fuels can implicitly be defined as substances used to add heat energy to a system through combustion or other processes. Fuels are mostly hydrocarbons like kerosene, diesel, petrol, alcohol, paraffin and butane and can also be in the form of individually free reactive molecular substances like hydrogen or chemical composites like natural gas, coal, wood.The gaseous state substances used as fuels such as hydrogen, and natural gas (94% methane and 6% ethane) are usually made into a cryogenic state as in liquefied at very low temperature because of their low boiling point. It can easily be asserted by anyone that t he only purpose that fuels have in jet engines is to add energy but little do they know that the purposes grows as the speed of the aircraft increases. For instance, Kerrebrock (2002) stated that supersonic aircrafts which attains very high stagnation temperature that can create destabilization to the airframe structure, engine component and organic substances like lubricants, uses its fuel as a coolant to this parts or components.The energy added by the fuel burned per unit mass of air flow is called the heating value of the fuel and it is a very crucial parameter to be defined before any combustion process analysis is done on a jet engine since it shows how complete the combustion process is through efficiency. The heating value can either be said to be higher or lower depending on if the water product of combustion is a vapour or a liquid. Since the combustion process in jet engine produces vaporised water, the lower heating value of the fuel is used. The most frequently used fue ls for jet engines are kerosene jet A1, A2, JP10 and many more but diesel can also be used. The disadvantages of these fuels are their inevitable emission of toxic substances that contribute to greenhouse effect and their risk of depletion.Accordingly, this has been the driving force for the use of alternative fuels such as cryogenic hydrogen and natural gas which is believed will reduce toxic emissions. Besides, hydrogen is a carbon-free energy carrier and possesses almost no risk of toxic emission since most of its combustion product will be water Chiesa and Laozza (2005). Chapter 3 Turbofan Jet Engine 3. 1. Introduction Between 1936 and the next decade when turbofan engines were invented, people showed little or no interest in them as they described them to be a complicated version of a turbojet engine. However, in 1956, the benefits of turbofan engines started to be noticed as major companies like Rolls-Royce and General Electric began manufacturing them.Since then, it is been o ne of the most used jet engine for commercial purposes because of its low fuel consumption and less noise production. In fact, it has been concluded to be the most reliable jet engine ever manufactured El –Sayed (2008). The turbofan jet engine gas generator unit comprises of a fan unit, compressor section, combustion chamber and turbine unit. Fundamentally, a turbofan jet engine operates as a result of the compressors pressuring air and supplying it afterwards for further processing. The majority of the pressurised air is bypassed around the core of the engine through a duct to be mixed or exhausted whereas the rest of it flows into the main engine core where it combusts with the fuel in the combustion chamber.The hot expanded gas products from the combustion process passes through the turbine thereby rotating the turbine as it leaves the engine. Consequently, the rotating turbine spins the engine spool which in turn rotates the other turbo machinery in the engine. This cause s the front fan to pressurise more and more air into the engine for the process to start all over again in continuous state. The turbofan engine is believed to be the perfect combination of the turboprop and turbojet engine and as a result, its advantages are usually compared to that of the turboprop and turbojet. In fact, Kerrebrock (1992) said that turbofan engine provides a better way of improving the propulsive efficiency of a basic turbojet.It is asserted that at low power setting, low altitude condition and low speed, the turbofan engine is more fuel efficient and has better performance than a turbojet engine. Unlike turboprop engine where vibration occurs in the propeller blades at relative low velocities, the fan in the turbofan engine can attain high relative velocities of Mach 0. 9 before vibration occurs. Also, since the fan in turbofan engines has many blades, it is more stable than the single propeller so even if the vibration velocity is reached, the vibration will not destabilize the airflow because the vibrations are almost negligible. Since the flow into the diffuser of the turbofan is usually subsonic, there very slim chances of shock waves being developed at the entrance. 3. 2. Classification of Turbofan EnginesThere are various types of turbofan engine ranging from high and low bypass ratio, afterburning and non-afterburning, mixed and unmixed flow with multi-spool, after fan and geared or ungeared. The classification of the various types of turbofan engines is shown below in figure 1. Nonetheless, the type of turbofan engine that would be used for the purpose of this dissertation is a forward fan two spool mixed flow turbofan engine. This type of turbofan engine was chosen because it is the compromise of a simple and complex turbofan engine. This is said because it comprises of almost all the classes of a turbofan which are low bypass ratio, forward fan with mixed flow, twin spool with ungeared fan.Moreover, because of the mixed flow intro duced, it produces additional thrust in the hot nozzle compared to the high bypass and it can also permit the addition of afterburner which produces a lot of thrust while consuming a lot of fuel which makes it suitable for military application which shows little worry on fuel consumption. In essence, carrying out a study on this type of turbofan engine will be of great relevance to the military air force sector especially if new research is discovered. TURBOFAN ENGINES Low Bypass Ratio Aft Fan Forward Fan Nonafterburning Afterburning High Bypass Ratio Geared Fan Single Spool Short Duct Ungeared Fan Two Spool Mixed Fan and Core Flow Unmixed Flow Long Duct Three SpoolFigure 1 Classification of Turbofan Jet Engines (El-sayed, 2008) 3. 3. Major Components of Turbofan Engine 3. 4. 1. Diffuser or Inlet Diffuser is the first component that air encounters as it flows into the engine. Basically, the purpose of a diffuser is to suck in air smoothly into the engine, reduce the velocity of the air, increase the static pressure of the air and finally, supply the air in a uniform flow to the compressor. Given the fact that overall performance of an engine is highly dependent on the pressure supplied to the burner, it is necessary to design a diffuser that incurs the minimum amount of pressure loss.To demonstrate this, Flack (2005) stated that if the diffuser incurs a large total pressure loss, the total pressure in the burner will be reduced by the compressor total pressure ratio time this loss. In other words, a small pressure drop in the diffuser can translate into a significant drop in the total pressure supplied to the burner. Another point taken into consideration when designing a diffuser is the angle because if the angle is too big, there will be tendency of eddy flow generation due to early separation. The major causes of pressure losses in the diffuser are as follows. First, losses due to generation of shock waves outside the diffuser and it majorly occur in super sonic diffusers.Secondly, the loss due to the unfavourable or adverse pressure gradient of the diffuser geometry which makes the flow separate a lot earlier and generates eddies. This separation causes a convergent area which makes the velocity not to be reduced by much. Due to the separation, the wall shear deteriorates the static pressure even further. Further analysis done by El-Sayed (2008), describes ways of accounting for this losses like using Fanno line flow and combined area and friction. Thermodynamic Process Equation In this analysis, the loss due to heat transfer is negligible so the process can be adiabatic. The initial kinetic energy is used to raise the static pressure p0 to the total pressure ? =pt2pt0 (inlet pressure recovery) efficiency ? d=IdealReal=ht2s-h0ht2-h0 assuming the gas is ideal and the specific heat at constant pressure is constant efficiency ? d=Tt2s-T0Tt2-T0 simplifying the equation given that ht0=ht2=ht2s and Tt2=Tt0and pt2s=pt2 TtT0=1+? -12M02 and T tT0=ptp0? -1? pt2p0=1+ ? d? -12M02 -1 3. 4. 2. Fan And Compressors Compressor is a very crucial component for the operation of an engine in the sense that it prepares the air for the combustion process in the burner. The main purpose of a compressor as the first rotating component is to use its rotating blades to add kinetic energy to the air and later translate it into total pressure increase.There are basically two types of compressors which are the centrifugal and the axial compressor. Firstly, centrifugal compressor as the name implies changes the direction of an axial airflow to a radial outflow of the air. It was the early compressors adapted in jet engines. It comprises of three main parts which are the impellers, the diffusers and the compressor manifold. The purpose of the impeller is to change the direction of the flow from axial to radial and at the same time increases its static pressure. The diffuser slows down the airflow and further increase the static pressure as it is supplied axially by the compressor manifold to the combustion chamber.The centrifugal compressor is advantageous because the cost of manufacturing it is low compared to axial compressor and as a result is suitable for small engines like turboshafts and turboprops. It is also advantageous because the pressure ratios at single stage are higher than that of the axial compressor. The centrifugal compressor has the tendency of attaining low flow rates and as a result is ideally suitable for helicopters and small aircrafts which require low flow rates. On the other hand, the centrifugal compressor cannot attain high pressure ratio and so it is not suitable when high peak efficiency is required. It incurs a lot of losses due to the change in direction. Secondly, an axial compressor is the most reliable type of compressor and is usually applied when higher pressure ratios of up to 40:1 are required.An axial compressor does not change the axial flow direction of the air but increases the total pressure. Indeed, an axial compressor comprises of three major components which are the rotor with blades, stator can and the inlet guide vane. A stage is a combination of a stator and a rotor. The assembly of the full rotor blade and stator can form the number of stages in a compressor and the greater the number of stages, the higher the total pressure ratio. In this arrangement, the air flows into the inlet guide vane and then into the rotor and stator assembly where compression starts. Also, the length of the rotor and stator reduces along the whole unit which signifies a reduction in volume which induces the increase in pressure.A fan or low pressure compressor is a type of axial compressor but the only differences are that the blades are longer, the total pressure ratio is lower than the typical compressor and the number of stages is usually 1 or 2. The main purpose of creating a fan is to compress more air and to create a bypass air which can be used to generate addition thrust or used for mixing process. Fan Equation Process Given that, isentropic efficiency ? fan= Ideal CycleActual cycle=ht3s-ht2ht3-ht2 Since the specific heat is constant, the equation deduces to ? fan=Tt3s-Tt2Tt3-Tt2 Simplifying the equation whenpt3s=pt3, Tt3sTt2=pt3pt2? -1? , ? fan=pt3pt2 and ? fan=Tt3Tt2 ? fan=? fan? -1? -1? fan-1 Bypass Ratio=msma where ms is the bypass flow rate and ma is the engine core flow rate.For the high pressure compressor, the equations remain the same as that of the fan except the changes in station numbering and the bypass ratio. 3. 4. 3. Combustion Chamber/ Burner The combustion chamber as the Brayton cycle implies is the only source of heat energy addition to the system. Accordingly, the combustion chamber causes very significant increase in the temperature of the air which results in the air gaining enormous internal energy. This energy gained is extracted to be used to power the turbine while the rest is used to create highly accelerated gases from the nozzle. There are three types of combustor namely; the can combustor, the annular combustor and the cannular combustor.The main considerations when designing a combustion chamber is to ensure that the combustion process is complete with no fuel waste, the combustor should have long life materials because any failure can lead to engine explosion. The other consideration is that the air must be heated enough above the ignition fuel temperature in order to ensure stoichiometric combustion. Equations of the Combustion Chamber In the real process of the combustor, total and static pressure drops and the temperature also drop. The major causes of pressure losses are the high level of irreversibility or non-isentropic process and viscous effects in the burner. The burner pressure ratio ? =pt5pt4Burner temperature ratio ? b=Tt5Tt4 Since no work is done only heat transfer, the efficiency of the burner is analysed using the heating value NCV of the fuel used. Thus, efficiency ? b=hea t addedHeating value of fuel=ma+mfht5-maht4NCVmf Given that f=mfma, ? b= 1+fht5- ht4NCVf Equivalence Ratio of combustion It is the ratio of the actual fuel to air ratio of the combustion process to the stoichiometric fuel to air ratio. This ratio produces a means of classifying the combustion process to show whether it is a lean, rich or stoichiometric combustion. The mathematical expression for this is as shown below ? =Actual FARStiochiometric FAR 1 Rich combustion process 3. 4. 4. Turbine Turbine can simply be said to be the antonym of a compressor. In response, a turbine extracts molecular kinetic energy from the air and uses it to drive the turbo machineries which results in the pressure and temperature of the air to drop. If truth be told, Flack (2005) asserted that the turbine uses 70% to 80% of the total energy gained by the air in the combustion chamber to drive the turbo machineries while the remaining 20% to 30% is used to generate thrust in the nozzle.Since the geometry of a turbine have favourable pressure gradient unlike the compressor which is adverse, the efficiency of the turbine is usually very high. Since the turbine is the opposite of the compressor, it has exactly the same configuration of rotor and stator but the volume increase across it which induces the pressure drop. One major problem faced when design a turbine is the deterioration of the blades due to high inlet temperature from the combustion chamber. Based on this, (Song et al. 2002) demonstrated that General Electric uses about 16. 8% of the compressor air to cool the turbine blades of GE 7f engine. Turbine Equation Analysis Given that, Turbine efficiency ? T=ActualIdeal=ht6-ht5ht6s-ht5 T=Tt6-Tt5Tt6s-Tt5 Simplifying the equation given that pt6s=pt6 Tt6sTt5=pt6pt5? -1? ?T=pt6pt5 ? T=Tt6Tt5 ?T=? T-1? T? -1? -1 3. 4. 5. Exhaust Nozzle The nozzle is the final component of the jet engine that the air passes through. The main purposes of the nozzle is to add extra acceleration to the h igh velocity exiting air, reduces its total pressure to that of ambient condition and finally generate sufficient thrust. There are two conditions that occur in the exit of the nozzle depending on the ambient pressure. The first condition is termed under-expansion which occurs when the ambient pressure is less than the exit pressure of the gases.The result of this is that the exit velocity will be lower than it normally is and this makes the momentum component of thrust to be lower than ideal. On the other hand, it will create a positive thrust component for the pressure terms. The second case termed as overexpansion which occurs when the ambient pressure is greater than the exit pressure of the gases. Consequentially, the opposite of what happens in the under-expansion condition occurs where the pressure term is lower and the momentum is higher. Nozzle efficiency ? n=ActualIdeal=ht8-h9ht8-h9s=Tt8-T9Tt8-T9s for constant specific heat Using the steady state energy equation and balanc ing it out, U9=2ht8-h9 . When specific heat is constant U9=2cpTt8-T9 p9pt8=T9sTt8? -1? T9Tt8=11+? -12M92 p9pt8=11+? -12M92-1+ ? n ? n 3. 4.Thermodynamic Process and Cycle of Twin Spool Mixed Flow Turbofan Engine Before any explanation is done from Figure 2, the blue arrows represent the incoming air into the diffuser and the red represent the air flow into the core of the engine while the black arrow represent the bypass air flow through the fan. Finally, the brown arrow represents the air flow after the bypass air and the core air flow have mixed. Based on the arrangement of the turbofan engine in figure 2, it can be seen that air at ambient condition is sucked into the diffuser where the air velocity is reduced and some of its kinetic energy is used to increase the static pressure to the total pressure. The air exiting the diffuser enters the fan or low pressure compressor where it is compressed. Indeed, the molecules of the air gains kinetic and internal energy by colliding rapid ly with one another and as a result increase the enthalpy and static pressure.Also, in the fan, some of the compressed air is bypassed through a duct to be used for the mixing process later while the rest of the air enters into the high pressure compressor of the engine core. In the high pressure compressor, the air is further compressed where the enthalpy and pressure increases as it is released into the combustion chamber. Also, in the high pressure compressor, some of the air mass flow rate is bled out to be used to cool the turbine blades and for air conditioning in the aircraft. In the combustion chamber, the incoming fuel reacts with the air in an oxidation process at constant pressure where the by-product gases gain molecular kinetic energy thereby increasing the enthalpy.This high temperature gases escapes into the high pressure turbine where it is expanded and the gases lose some of their kinetic molecular energy as it enthalpy and static pressure reduces. In other words, i t can be said that the molecular kinetic energy of the gases is being converted to mechanical work which is used to power the high pressure spool. Consequently, the gases enters into the low pressure turbine where it is further expanded to a lower pressure and enthalpy as their molecular kinetic energy is converted to mechanical work to power the low pressure spool. These gases escaping from the low pressure turbine enters the mixing zone or mixer after it has lost most of its total enthalpy and mixes with the bypassed cold air from the duct to further reduce its enthalpy as that of the cold air increases.In other words, the cold air absorbs some of the heat energy from the hot gases until they both attain equilibrium enthalpy. The mixture of the cold air and hot gases both escape at the same equilibrium enthalpy and pressure through the nozzle where their velocity is increased and the pressure is reduced considerably to that of the ambient condition. Furthermore, the exhausted high velocity gases is used to produced thrust for propulsion according to Newton’s third law of motion (In every action, there is equal and opposite reaction). 2 4. 5 6 4 13 0 HPC DIFFUSER FAN/LPC HPT LPT NOZZLE COMBUSTION CHAMBER 2. 5 3 5 8 16 BYPASS DUCT HP Spool LP Spool MIXING ZONEFigure 2 Layout of a Forward Fan Twin Spool Mixed Flow Turbofan Engine P0 P3 P4. 5 P5 P8 P6 P2. 5 P2 P13 P4 ENTROPY (S)(kJ/kg) TEMPERATURE (K) Figure 3 T-S Diagrams for the Forward Fan Twin Spool Mixed Flow Turbofan Engine Chapter 4 Mathematical and Gas Turb 11 Modelling of the Engine 4. 1. Station Numbering and Assumptions Station numbering is a very crucial step that has to be taken when analysis of any thermodynamic system involving many processes is to be done. Moreover, station numbering contributes immensely to showing how the properties of one process relate to another and how the interaction between these processes derives the functional relationship of the thermodynamic system.Returning to the work in hand, the station numbering system that has been adopted for this work on a JT8D-15A turbofan engine is in accordance with the Aerospace Recommended Practice (ARP) and it is shown in figure 2. Assumptions The following assumption were made based on Mattingly (2002) and Kurzke (2007) in order to perform the modelling as listed below * The air flow through the engine is assumed to be steady and one dimensional * The fan and the low pressure Compressor are driven by the low pressure turbine * The overall engine is assumed to have no bleeds in mass flow or power off-take in turbine. * The nozzle of the engine is choked which means the exit pressure will be greater than the ambient pressure. The air is assumed to act as a half ideal gas where the specific heat and ratio is dependent on temperature only. * The areas of each station of the engine is assumed to be constant 4. 2. Design Point Cycle Analysis of the Turbofan Engine The off-design or performance cycle analysis cann ot be done without the design point cycle being defined. The design point cycle in this analysis is obtained using exactly the same data used in the actual test analysis for a JT8D-15A turbofan engine operating at sea level with maximum take-off thrust as shown in (â€Å"JT8D Typical Temperature and Pressure†) and (â€Å"ICAO†). Some of the input parameters such as the isentropic efficiencies and pressure ratios from the actual test data had to be calculated.Since not all the input parameters were given from the actual test data, some of the parameters like inlet corrected mass flow rate, diffuser pressure ratio and efficiency; mechanical spool efficiency had to be guessed in order to complete the analysis and the data are represented below in Table 1. With all the Input Parameter being specified as shown in table 1, the design point cycle simulation of the JT8D-15A turbofan Engine using the Gas Turb 11 software can then be performed. All the steps taken to model the m ixed flow turbofan engine on Gas Turb 11 is clearly represented in the algorithm shown in figure 3 below. COMPONENT| INPUT PARAMETER| | DIFFUSER| Pressure Ratio (? d)| 1| | Inlet Corrected Mass Flow Rate (mc2)| 138. 618 kg/s| FAN| Pressure Ratio (? fan)| 2. 054| | Isentropic Efficiency (? fan)| 0. 78| | Bypass Ratio (? )| 1. 08| Low Pressure Compressor (LPC)| Pressure Ratio (? LPC)| 4. 7| | Isentropic Efficiency (? LPC)| 0. 88| | Nominal Low Pressure Shaft Speed (NLP)| 8160RPM| High Pressure Compressor (HPC)| Pressure Ratio (? HPC)| 3. 77| | Isentropic Efficiency (? HPC)| 0. 864| | Nominal Low Pressure Shaft Speed (NHP)| 11420RPM| Combustion Chamber (cc)| Pressure Ratio (? CC)| 0. 934| | Isentropic Efficiency (? CC)| 0. 99| | Burner Exit Temperature (TIT)| 1277. 15K| High Pressure Turbine (HPT)| Isentropic Efficiency (? HPT)| 0. 9| | HP Spool Mechanical efficiency (? m)| 1| Low Pressure Turbine (LPT)| Isentropic Efficiency (? LPT)| 0. 91| | LP Spool Mechanical efficiency (? m)| 1| T able 1 Input Parameters for the Design Point Cycle Simulation STARTSpecify all the input data gotten from the actual test data as shown in Table 1 Run the Gasturb 11 software and select mixed flow turbofan from the drag down Tab list. Set the scope to ‘More’, set the Calculation Mode as Design and click ‘Run’ Choose the Units to either Imperial or SI and Select the type of fuel from to drop down list to Kerosene, Natural Gas or Hydrogen Estimate the inlet Corrected mc2 Mass Flow rate to the FAN/LPC Choose ‘Single Cycle’ for ‘Select a Task ‘Option and click ‘Run’ Check if the Thrust, SFC, ? HPT, ? LPT and EPR are within (0-10) % of the actual test Experiment END YES NO Figure 4 Design Point Cycle Simulation Algorithm Using Gas Turb 11 Verification of the Design Point simulation ResultsSince not all the input parameters were specified in the actual test data and some of them had to be guessed, it is without any doubt that errors are bound to generate in the simulation results using the Gas Turb 11 software. In order to ensure that the errors accumulated in the simulation were within range, the major output parameters obtained such as net thrust, fuel flow rate, Engine exit pressure ratio, etc were compared to the actual test data as shown in Table 2 and the error range was calculated to be between 0. 25% to 8. 5% which is within an acceptable range. PARAMETERS| ACTUAL TEST DATA| SIMULATED DATA USING GASTURB 11| Net Thrust| 69307. 74| 69320| Engine Exit Pressure Ratio P8P0| 2. 09| 2. 167|Burner Fuel Flow| 1. 100843| 1. 09781| HPT pressure Ratio (? HPT)| 0. 415| 0. 449| LPT Pressure Ratio (? LPT)| 0. 3294| 0. 3514| HPT temperature Ratio (? HPT)| 0. 8097| 0. 8435| LPT temperature Ratio (? LPT)| 0. 7718| 0. 793| Table 2 Comparison Table for the Actual Test Data and Simulated Data Using GasTurb 11 4. 3. Off-Design Point Cycle Simulation of the Turbofan Engine The off-design or performance cycle simulatio n takes into account the concept of module matching of each component through performance maps. This cycle analysis enables the determination of different operating point of the engine at a given design point of the engine.Considering the work in hand, the design point have been defined and verified for the JT8D-15A turbofan engine operating at sea level with maximum take-off thrust which means that different operating points of the engine can be defined with the concept of off-design module matching of the engine. Indeed, the off-design operating point that was considered for the parametric analysis in this work was 30,000ft at M0 0. 8 for the turbofan engine. The off-design modelling of the JT8D-15A engine for the operating point of 30,000ft at M0 0. 8 based on the reference design point defined earlier is clearly demonstrated as follows. The off-design performance cycle simulation may contain some errors because of the component performance maps that were used for the simulation. 4. 3. 1. Module/Component Matching This process only applies to the off-design performance cycle point of the engine.It can simply be defined as the act of synchronising each component of a jet engine to coexist as a unit in order to derive the overall performance characteristics of the jet engine. Component matching involves the process closely studying the ramifications of the actual jet engine overall performance behaviour on the components major characteristics such as pressure ratio, temperature ratio, efficiency and spool speed. This process introduces the concept of empirically determined component performance maps that establishes the relationship between the thermodynamic properties and the geometry of the jet engine itself. 4. 3. 2. Off-Design Component Modelling Diffuser The diffuser was assumed to be adiabatic and the pressure ratio ? d=1 The Isentropic Efficiency was assumed to be 1 For Sea Level,Pamb=101325pa , Tamb=288. 15K For 30,000ft and M0 0. 8, Tamb=288. 15-0. 0 065? 9144 =288. 15-59. 436 =228. 71K Pamb=101325? Tamb288. 155. 2561 =30. 09kpa Tt1=228. 71? 1+? -12M02 =228. 71? 1+1. 4-12? 0. 82 =258K pt1p0=1+ ? d? -12M02 -1 pt1=30. 09? 1+ 1? 1. 4-120. 821. 41. 4-1 pt1=45. 8674kPa pt1=pt2 Tt1=Tt2 Fan and Low Pressure Compressor The inlet corrected mass flow rate is estimated as 138. 618kg/s , As for the off design simulation using the component performance maps for the altitude of 30000ft and Mach no. 0. 8, the actual spool speeds and inlet mass flow rate are calculated based on the estimated inlet corrected mass flow rate as shown below.Low and High pressure spool mechanical efficiency is assumed to be=1 HP spool Speed=11420RPM, LP spool Speed=8160RPM m2=Pt2PSTD? mc2Tt2TSTD =45. 878101. 325? 138. 618258288. 15 Actual Mass flow rate m2=66. 3323kg/s N=Tt2TSTD? NcLP=228. 71288. 15? 8160=7722 RPM The calculated actual mass flow rate and spool speed were used to evaluation the isentropic efficiency and the pressure ratio of the LPC for that operatin g condition from the compressor performance map. Figure 5 Example of a Compressor Performance Map/Curve The diagram above in figure 4 depicts a typical compressor performance map that was used for the off-design point analysis in this work.It can be seen that the x-axis represents the inlet corrected mass flow rate mc2 into the compressor, the y-axis represents the compressor pressure, the red contour lines represents the isentropic efficiencies and the black curved lines represent the relative corrected spool speed. To add to that, the red dash line that ends the speed lines and efficiency lines represent the surge margin which is also known as the stall line that must be avoided since the flow will become unstable in that region. In this work, the inlet corrected mass flow rate and spool speed were calculated which were interpolated on the performance map to obtain the pressure ratio and the isentropic efficiency.For instance, the yellow dot on the map represents a design point tr aced for a given pressure ratio, High Pressure Compressor The inlet corrected mass flow rate into the HPC mc2. 5=mc21+? mc2. 5=138. 6182. 08=66. 64kgs m2. 5=Pt2. 5PSTD? mc2. 5Tt2. 5TSTD N=Tt2. 5TSTD? NcHP The same equation used for the LPC is used to calculate the actual mass flow rate and spool speed which is used to evaluate the isentropic efficiency and pressure ratio when it is operating at an altitude of 30000ft at M0 =0. 8. Verification of the off-design modelling for 30000ft at Mo 0. 8 In order to verify the simulation result gotten for the operational design point of 30000ft at M0 0. , the actual test data results gotten from Mattingly, Heiser and Pratt (2002) for the same operating condition was compared. Due to the difficulties in obtaining a lot of output parameters for this operating point, the result will be verified with only the net thrust generated and the specific fuel consumption. Indeed, the error accumulated was 1. 71% for the net thrust and 0. 83% for the specif ic fuel consumption. PARAMETERS| ACTUAL TEST DATA| SIMULATED DATA USING GASTURB 11| Net Thrust (lb)| 4920| 4836| Specific Fuel Consumption(lb/lbh)| 0. 779| 0. 7855| Table 3 Comparison Table for the Actual Test Data and Simulated Off-design Data Using GasTurb 11 Chapter 5Methodology, Results and Discussions Given that the design point of the JT8D-15A turbofan engine at sea level has been obtained and verified with the actual test data, the operating point of 30000ft at M0 0. 8 was simulated and obtained which now served as the design point for the analysis in this work. Moreover, the procedure taken to define this design point of 30000ft at M0 0. 8 of the JT8D-15A turbofan engine has been clearly stated earlier which gives the permission to conduct the parametric cycle study of the turbofan engine. The parametric cycle studies were done for three different cases for the operational design point of 30000ft at M0 0. of the JT8D-15A turbofan engine as explained as follows. 1. The first parametric analysis case 1 aim to create an understanding of the effects of varying major design parameters on the performance parameters of the turbofan engine when some of the design choices are kept constant. In other words, the bypass ratio and thermal limit parameter (turbine inlet temperature) were varied when the design choices such as the compressor pressure ratio, fan pressure ratio and isentropic efficiencies were kept constant in order to investigate their effects on the performance parameters such as the net thrust, specific fuel consumption, propulsive efficiency, thermal efficiency, and fuel-air-ratio.Much interest is shown nowadays in using alternative fuels like hydrogen and Natural gas in efforts to reduce the cancer known as pollution and the risk of depletion of energy resources. Based on this, conducting a research that focuses of comparing different fuels consumption rate, their risk of pollution and their contribution to the performance of the engine will be re ally valuable. Based on this, a parametric analysis had to be done on the JT8D-15A turbofan engine using three different fuels which are the design point fuel kerosene, hydrogen and natural gas. Since the original design point of the JT8D-15A turbofan was obtained using kerosene fuel, the design points of using hydrogen and natural gas was obtained using the same design choices as that of kerosene.Now that the design points of the JT8D-15A turbofan engine had been defined when using the three different fuels, it had given a go ahead to perform whatever parametric cycle studies of the turbofan engine using the three fuels. In order to compare the performance characteristics of the turbofan engine when it is using the three different fuels, different approaches had to be devised to compare them effectively on a rational basis which defines the last two parametric analysis cases as follows. 2. The second case of parametric analysis was that the fuel flow rate would be kept constant for the three fuels that would be used as the bypass ratio is varied with design choices remaining the same. 3.The third case of study was to make the energy supply into the combustion chamber of the turbofan engine the sa

Friday, January 10, 2020

Business Ethics and Their Role in Organizational Development

Business Ethics and their role in Organizational Development Brett Ballesteros National University In business today there are many different forms of operation and ways of achieving a successful firm. Organizational behaviors are key to insuring a business withstands the test of time and does so through the individual employees that are the foundation to firms around the world. These individuals must live and work by a set of ethics that the company and their everyday lives have instilled in them. Ethics can either make or break a company through employees application of this concept in the workplace.Ethics can be defined as a â€Å"moral philosophy involving systematizing, defending, and recommending concepts of right and wrong behavior† (Fieser, 2003). In business, these ethics need to reflect the ideology and morals a company is built upon through the individuals and groups that represent a firm. The code of ethics for any business is put in place to ensure that their posi tion on integrity and conduct are not compromised. A business must maintain a certain level of integrity in order to be trusted not only by consumers, but its employees as well, as this is the cornerstone for corporate relationships.This code of ethics is typically based on the basic principles of right and wrong, whereas the individual must be able to differentiate between the two when formulating decisions that will directly affect the companies integrity. These decisions may not be entirely clear due to the nature and uniqueness to the different possible situations that may arise. Business ethics are there to make sure the business itself is governing good behavior. That’s why there are certain laws to prevent companies from over-working employees, or making sure children are not working for them as well.When companies use business ethics, it gives them a chance to show their morals. Every company should have a set of morals that they conduct their business by. Having thes e moral beliefs in a company gives the business something to set the rules by. It makes it much easier for managers employees to make their decisions based on their set of business ethics because that way they have a set of morals they can abide by when handling business decision-making. â€Å"Consequential theories of ethics emphasize the consequences or results of behavior.John Stuart Mill’s utilitarianism, a well-known consequential theory, suggests that right and wrong are determined by the consequences of the action. â€Å"Good† is the ultimate moral value, and we should maximize the most good for the greatest number of people† (Nelson & Quick, 2012). It’s only obvious that good business ethics include having good moral as is. No one person wants to work for a company that they fell has bad morals. According to the company, Levi Strauss & Co. they set their business ethics up to: honesty, promise-keeping, fairness, respect for others, compassion, and integrity.They state, â€Å"As we seek to achieve responsible commercial success, we will be challenged to balance these principles against each other, always mindful of our promise to shareholders, that we will achieve responsible commercial success† (Stillman). A smart business knows that it must set ethics, character, and personal integrity inside each of its employees. This way each employee knows what is expected of them and that they are comfortable in their workplace. Not every job that I have attained has had good business ethics, but the ones that do are the ones that have stuck with me.If the employer treats their employee right it can only reap great reward. If an employee loves working for their company they are going to want that business to succeed, so they will promote the place and receive more sales that way. When it comes down to it, every person wants to work for a company who has great morals. Whether people actually abide by these â€Å"good† mora ls in life, they always tend to want to find a company who will keep these business ethics in mind. Good business ethics plainly mean that the people working there are going to have good morals.Having good business ethics means the company is going to receive trust of their employees which is going to build business partners and clients alike. In order for companies to attract and retain valuable employees, good ethic treatment is necessary. Every company has a code that they set their ethics to, and as long as they abide by those codes they are going to have people who are willing to work hard for them, also when these employees work hard it makes sense that the company should provide ethic praise.

Thursday, January 2, 2020

My Original Plan Was To Create A Manual That Teaches The

My original plan was to create a manual that teaches the interns and staff how to properly do things with referrals, data entry, scheduling, etc. The purpose was to provide a protocol on how things should be completed by each therapist, and eliminate the possibility of miscommunication. My first approach was to speak with the other interns to address the concerns they had with the trainings they received. I spoke with each intern individually to see how they felt about the training process including pros and cons of their experience. In conclusion, 7 out of 8 interns felt they would have benefitted from more proper training at the beginning of the internship. Many of them felt like it was a disservice to them and a disservice to their†¦show more content†¦If an intern has questions on how to do something, they can refer to the manual. I will include a section at the end with a â€Å"frequent asked questions† page to address the common questions that other interns had during the training process. I wanted to speak with the director to discuss data entry, treatment planning, and the psychosocial packet to write the manual precisely how he wants the interns to be trained. My plan was to go over each page in the manual individually with the director so I could get his approval for the project. My hopes were to make a copy of the training manual for the director, supervisor, and the administrative staff so it can be easily accessible for the incoming interns next year. There were two biggest challenges when beginning the project that I did not expect to be as big of an issue: limited time to discuss the manual with my supervisor, and the limited time I had to work on it. The demand for services remained high and my caseload doubled in a span of a few weeks. I was still receiving cases at the end of March, and had little time outside of managing my caseload. The director continued to remain extremely busy, and the meetings we had scheduled were gettin g cancelled at least twice a month. In the middle of March, the Office of Mental Health decided to do a big audit for the clinic and everything became chaotic. Due to issues with previous staff, many cases were missing significant paperwork and I wasShow MoreRelatedThe And Treatment Plan For Therapy Sessions And Medication Management2290 Words   |  10 Pagesobjective that we made for him is to help identify the triggers that cause him to get angry. The second objective was to utilize various outlets two times a week to help him destress when he is feeling overwhelmed. He mentioned that he enjoys doing karate, boxing, and running and would like to make it a priority for his mental health. 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