TD Course File

Department of Mechanical Engineering Course File: Thermodynamics

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MECHANICAL ENGINEERINGII/IV (I-SEMESTER) R09 Syllabus

THERMODYNAMICS - Course File

Prepared By:Name Department Date Version

P. Badari Narayana Associate Professor, 1.0

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LECTURE SCHEDULE

UNIT

PERIOD NO.

TOPICS

I

1 System, control volume, surroundings, boundaries, universe, types of systems.

2 Macroscopic, microscopic views, concepts of continuum3 Thermodynamic equilibrium, state, property, process, cycle-

reversibility.4 Quasi-static process, 5 Irreversible process, causes of irreversibility-energy in state and in

transition.6 Types, work and heat, 7 Point and Path Function8 Problems & Exercise

II

1 Zeroeth law of thermodynamics-concept of equality of temperature.2 Principles of thermometry-reference points3 Constant Volume gas thermometer. 4 Scales of temperature, ideal gas scale.5 PMM-I, Joule’s Experiments6 First Law of Thermodynamics, Corollaries7 First Law Applied to a Process8 First Law Applied to a flow system9 Steady Flow Energy Equation

III

10 Limitations of First Law1 Thermal Reservoir2 Heat Engine, heat Pump, Parameters of performance3 Second law of Thermodynamics4 Kelvin Plank & Clausius Statements5 Their Equivalence/Corollaries6 PMM –II 7 Carnot Principle, Carnot Cycle & Its Specialties 8 Thermodynamic Scale of temperature9 Clausius Inequality10 Entropy11 Principle of Entropy Increase- Energy Equation12 Availability & Irreversibility13 Thermodynamic Potentials14 Gibbs & Helmholtz Functions15 Maxwell Relations16 Elementary Treatment of Third Law of Thermodynamics

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IV

1 Pure Substances, P-V-T Surfaces2 T-S & H-S diagrams3 Mollier Charts4 Phase Transformations5 Triple point at critical state properties during Change of

Phase6 Dryness Fraction-Clausius-Clapeyron Equation Property

Tables-Mollier Charts 7 Various Thermodynamic Processes and Energy transfer8 Steam Caloremetry

V

1 Perfect Gas Laws –Equation of State, Specific and Universal gas constants

2 Various Non-Flow Processes, Properties, End States3 Heat & Work transfer4 Changes in Internal Energy5 Throttling and Free Expansion Process6 Flow Processes7 Deviations from Perfect Gas Model8 Vanderwaals Equation of State9 Compressibility Charts10 Variable Specific Heats, Gas Tables

VI

1 Mixtures of Perfect Gases2 Mole Fraction, Mass friction Gravimetric and Volumetric

Analysis3 Dalton’s law of Partial Pressures4 Avogadro’s Law of Additive Volumes5 Mole Fraction, Volume Fraction, Partial Pressure6 Equivalent Gas Constant7 Molecular Internal Energy, Enthalpy, Specific Heats and

Entropy of mixture of perfect gases and vapour 8 Atmospheric Air and Psychometric Properties9 Dry Bulb temperature, Dew point Temperature, TDic Wet

bulb temperature10 Specific humidity, Relative humidity, Saturated Air, vapour

pressure, degree of Saturation11 Adiabatic Saturation, Carrier’s Equation-Psychometric Chart

VII

1 Power Cycles: Power Cycles : Otto, Diesel,2 Dual Combustion cycles3 Sterling Cycle, Atkinson Cycle,4 Ericson Cycle, Lenoir Cycle5 Description and representation on P–V and T-S diagram6 Thermal Efficiency7 Mean Effective Pressures on Air standard basis8 comparison of Cycles9 Power Cycles: Power Cycles : Otto, Diesel,

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VIII

1 Brayton and Rankine cycles2 Performance Evaluation3 combined cycles -14 combined cycles -25 Bell- Coleman cycle 6 Performance Evaluation of Bell-Coleman cycle7 Vapour compression cycle8 Performance Evaluation

Text Books:

1. Engineering Thermodynamics /P.K. Nag - TMH , III Edition2. Thermodynamics – An Engineering Approach- Yunus Cengel & Boles / TMH

Reference Books:

1. An Introduction to thermodynamics – YVC Rao / University Press 2. A Solution manual to Introduction to Thermodynamics, YVC Rao/

Thermodynamic Press 3. Engineering Thermodynamics – Jones & Dugan4. Thermodynamics – Robert Balmer, Jaico Publications5. Thermodynamics by J.P. Holman, McGrawHill 6. Engineering Thermodynamics – K. Rama Krishna, Anuradha Publishers.7. Fundamentals of Thermodynamics – Sonntag, Borganakke and Vanwylen – John

Wiley & Sons (ASIA) Pte Ltd.

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UNIT – I THERMODYNAMICS

Questions

1. What is a Thermodynamic system?

2. What is the difference between a closed system and an open system?

3. What is a Thermodynamic Cycle?

4. What is the difference between intensive and extensive properties?

5. Can mass cross the boundaries of a closed system? How about energy?

6. What is a quasi-equilibrium process? What is its importance in engineering?

7. What is the concept of continuum? How do you define density and pressure using

this concept?

JNTU External Questions:

1. (a) Distinguish between path function and point function.

(b) Differentiate between flow and non-flow process. [8+8]

2. (a) Show that Work is a path function and not a state function. (b) Justify the statement that work and heat are not properties. [8+8]

3. (a) Explain thermodynamic system, surroundings and universe, illustrate the same with examples. (b) Distinguish between closed system, open system and isolated system with

Suitable examples.

4. Define the term property. State the differences between extensive, intensive

and specific properties of a thermodynamic system. Give few examples for each. [8M]

5. a) Distinguish between Microscopic and Macroscopic approaches in Thermodynamics b) Explain the following terms

i) State ii) Process iii) Cycle [8+8]

6) a) What is Quasi – Static process and explain its characteristics features b) 1 Kg of a fluid is compressed reversibly according to a law PV=0.25 where ‘P’ is in

bar and ‘V is in m3 /kg. The final volume is ¼ of initial volume. Calculate the work

done on the fluid and sketch the process on a P-V diagram [8+8]

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7) a) Show that energy is a property of the system b) A closed system undergoes a reversible process at a constant pressure process of 3.5

bar and its volume changes from 0.15m3 to 0.06 m3. 25KJ of heat is rejected by the

system during the process. Determine the change in internal energy of the system.

8. a) What are the different types of thermodynamics systems? Explain with examples b) Discuss Homogenous and heterogeneous systems

9. Define : Non-flow work and flow work , Extensive properties and intensiveproperties, Boundary and surrounding of a system [16]

10. (a) Define the term property. State the differences between extensive, intensiveand specific properties of a thermodynamic system. Give few example for each.

(b) A mass of 2.5 kg of air is compressed in a quasi static process from 0.1 MPa to0.7 MPa for which PV = constant. The initial specific volume is 0.80 m3/kg.Find the work done by the piston to compress the air. [8+8]

11. (a) What is a thermodynamic system? What is the difference between a closed system and an open system? Give few examples for closed and open systems.

(b) An engine cylinder has a piston of area 0.12 m2 and contains gas at a pressure of 1.5 MPa. The gas expands according to a process which is represented by a straight line on a pressure-volume diagram. The final pressure is 0.15 MPa.Calculate the work done by the gas on the piston if the stroke is 0.30 m.[8+8]

12. a] What is meant by quasi static process and explain any practical example of such process. b] A system with initial internal energy of 300KJ is receiving heat of 280KJ at constant volume process and rejects heat of 260KJ at constant pressure when 60KJ of work is done on the system. The system is brought to its original state by an adiabatic process. Calculate the adiabatic work and value of internal energy at salient points. [4+12]

13.. (a) Explain the control volume and its significance.(b) If a gas of volume 6000 cm3 and at a pressure of 100 kPa, is compressed

quasistatically to pV2=constant until the volume becomes 2000 cm3. Calculate the final pressure and the work transfer. [6+10]

14. (a) Energy is a point function. Explain and prove.(b) Prove that heat and work are path functions. [8+8]

15. (a) What do you understand by state function and path function?

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(b) Prove that work is a path function and properties are point functions. [6+10]

16. (a) Differentiate the cyclic process and non cyclic process. (b) A vacuum gauge connected to a tank reads 30 Kpa at a location where the

barometer reads 755 mm Hg. Calculate the absolute pressure in the tank assuming density of Hg to be 13,590 kg/m3. [6+10]

17. (a) Explain thermodynamic system, surroundings and universe, illustrate the same with examples. [8]

(b) Distinguish between closed system, open system and isolated system with suitable examples. [8]

18. Discuss where the following quantities can be used as properties are not.(a) R P dV+R V dP(b) R P dV(c) R V dP

19. (a) Define the terms ’system’ , ’surrounding’ and ’boundary’ of a system.(b) Define and differentiate between the following cycles:

i. Closed cycleii. Open cycle.

20. (a) Define thermodynamic work and prove that work is a path function.

21. b) Discuss the concept of continuum in thermodynamics.

21. a) Define and explain the following terms:(i) Thermodynamic equilibrium.(ii) Quasi-static process.

b) Gas from a bottle of compressed helium is used to inflate an inelastic flexible balloon, originally folded completely flat to a volume of 0.5 m3. If the barometer reads 760 mm Hg, what is the amount of work done upon the atmosphere by the balloon?

22. a) What is the difference between point and path function? Give sufficient number of examples for each.b) Differentiate between intrinsic and extrinsic, and intensive and extensive properties. c) Explain the concept of thermodynamic work and differentiate it with mechanical work.

23. a) Explain thermodynamic system, surroundings and universe. Illustrate the same with examples. b) Distinguish between closed system, open system and isolated system with suitable examples.

23. (a) What is thermodynamic equilibrium? Explain the significance of it in quasi-static process?

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24. (a) Explain thermodynamic system, surroundings and universe, illustrate the same with examples.(b) Distinguish between closed system, open system and isolated system with suitable examples.

25. (a) Discuss the concept of continuum in thermodynamics.(b) What do you mean by property? Distinguish between intensive and extensive Properties.

26. (a) Distinguish between closed and open systems by giving practical examples.(b) A computer in a closed room of volume 200m3 dissipates energy at a rate of10kW. The room has 50kg wood, 25kg steel and with all material at 3000k; 100kpa. Assume all the mass heats up uniformly, how long will it take to increase the temperature 100c.

27. (a) Explain the terms state, path, process and cyclic process.(b) Discuss the macroscopic and microscopic point of view of thermodynamics.

28. (a) Show that work is a path function and not a state function.(b) Justify the statement that work and heat are not properties.

29. (a) Write the differences between system and control volume.(b) A gas undergoes a reversible non-flow process according to the relation P =(-3V+15)where V is the volume in m3 and P is the pressure in bar. Determine the work done when the volume changes from 3 to 6 m3. [6+10]

30. A fluid contained in a horizontal cylinder fitted with a frictionless leak proof piston,is continuously agitated by means of a stirrer passing through the cylinder cover. The cylinder diameter is 0.4 m. During the stirring process lasting 10 minutes, the piston slowly moves out a distance of 0.485 m against the atmosphere. The net work done by the fluid during the process is 2 kJ. The speed of the electric motor driving the stirrer is 840 rpm. Determine torque in the shaft and power output of the motor. [16]

31 . A gas expands according to the equation PV=100, where P is the pressure in KPaand V is the specific volume in m3/kg. The initial pressure of the gas is 1000 KPaand the final pressure is 500 KPa. The gas is then heated at constant volume backto its original pressure of 1000 KPa. Determine the work of combined process. Alsosketch the process on P-V coordinates. [16]

32. (a) Define the term property. State the differences between extensive, intensiveand specific properties of a thermodynamic system. Give few example for each.

(b) A mass of 2.5 kg of air is compressed in a quasi static process from 0.1 MPa to 0.7 MPa for which PV = constant. The initial specific volume is 0.80 m3/kg. Find the work done by the piston to compress the air. [8+8]

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33. (a) Write the differences between system and control volume.(b) A gas undergoes a reversible non-flow process according to the relation P = (-3V+15)where V is the volume in m3 and P is the pressure in bar. Determinethe work done when the volume changes from 3 to 6 m3. [6+10]

34 . A gas undergoes two processes that are in series. The first process is an expansionthat is carried out according to the law PV = constant, and the second process is a Constant pressure process that returns the gas to the initial volume of the first process. The start of the first process is at 400 KPa and 0.025 m3 with the expansion to 200 KPa. Sketch the process on a P-V diagram, and determine the work of the combined process. [16]

35. (a) What are different forms of work energy? Explain each briefly.(b) Why does free expansion have zero work transfer? [10+6]

36. (a) State and study the thermodynamics with the view point of microscopic andmacroscopic approach.(b) The properties of a closed system undergo change following the relation PV=4where P is in bar and V in m3. Calculate the work done when P increases from 2.5 bar to 8 bar.

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UNIT – II THERMODYNAMICS

Questions1) What is a Zeroeth law of Thermodynamics?

2) Define Thermometric Property.

3) What is Thermometer?

4) What is a fixed point? What is a Standard Reference point in the thermometry?

Define it.

5) What is a Constant Gas Volume Thermometer? Why is it preferred to Constant

Pressure Gas thermometer?

6) What do you understand by Ideal Gas Temperature Scale?

7) How can the ideal gas temperature for the steam point be measured?

8) How can the ideal gas temperature for the steam point be measured?

9) How does Resistance thermometer measure temperature?

10) State First law of thermodynamics undergoing a cycle?

11) What is the property introduced by First law of Thermodynamics?

12) State the first law for a closed system undergoing a change of state.

13) Show that energy is a property of a system.

14) Define Internal Energy. How is energy stored in molecules and atoms?

15) Differentiate between the standard symbols of E & U.

16) What is the difference between Heat and Internal Energy?

17) Define Specific Heat at Constant Volume and at Constant Pressure.

18) What is PMM I? Why is it impossible?

19) Explain System Approach and Control volume Approach in the analysis of a Flow

process.

20) What is a Steady Flow process?

21) Under What condition S.F.E.E reduces to Euler’s Equation.

22) How does Bernoulli’s Equation Compare with S.F.E.E?

23) What will be the velocity of a fluid leaving a nozzle if the velocity of approach is

very small?

24) Show that Enthalpy of a fluid before Throttling is equal to After Throttling.

25) Write the General Energy Equation for a variable Flow Process.

26) What is the System Technique in Bottle Filling Process?

27) Explain the Control Volume Technique in a variable Flow process.

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1) (a) Define and explain Zeroeth law of thermodynamics.(b) Distinguish between adiabatic and isentropic process.(c) Identify the proper type of system in each case and explain the reason for yourchoice.i. Electric generatorii. Domestic tea kettleiii. Electric faniv. A living human being.

2) A mass of 8 kg gas expands within a flexible container so that the p-v relationship is of the form pv1.2 = const. The initial pressure IS 1000 kPa and the Initial volume is 1 m3. The final pressure is 5 kPa. If the specific internal energy of the gas decreases by 40kJ/kg, find the heat transfer in magnitude and direction.

3) The air speed of a turbojet engine. in flight is 270 m/s. Ambient air temperature is 15°C. Gas temperature at outlet of nozzle is 600° C. Corresponding enthalpy values for air and gas are respectively 260 and 912 kJ/kg. Fuel-air ratio is 0.0190. Chemical energy of the fuel is 44.5 MJ/kg. Owing to incomplete combustion 5 % of the chemical energy is not released in the reaction. Heat loss £Tom the engine is 21 kJ/kg of air. Calculate the velocity of the exhaust jet.

Process U (kJ) Q(kJ) W(kJ)1-2 -50 - 302-3 - 40 -503-4 60 50 -4-1 - - 80

UNIT – III THERMODYNAMICS

Questions

1) What are the Limitations of First Law.

2) What is the qualitative difference between heat and work? Why are the heat and

work not completely interchangeable forms of energy.

3) What is a Cyclic Heat Engine?

4) Explain a heat engine cycle performed by a closed system.

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5) Explain the heat engine cycle performed by a steady flow system.

6) Define the Thermal Efficiency of a heat engine cycle. Can this be 100%?

7) Draw block diagram showing the four energy interactions of a cyclic heat engine.

8) What is the thermal Energy Reservoir? Explain the terms Source and Sink.

9) What is the mechanical energy reservoir?

10) Why can all processes in a TER and MER be assumed to be quasi-static?

11) Give Kelvin-Plank Statement of Second Law of thermodynamics.

12) To produce net work in a thermodynamic cycle, a heat has to exchange heat with

two thermal reservoirs. Explain.

13) What is PMM II ? Why is it impossible?

14) Give the Clausius Statement of Second law of Thermodynamics.

15) Explain the operation of a cyclic Refrigeration plant with a block diagram.

16) Define COP if a Refrigerator.

17) What is a Heat pump? How does it differ from a Refrigerator?

18) Consider the energy generated by a TV set. What is a suitable choice for a

thermal energy reservoir?

19) What are the four processes that make up the Carnot cycle?

20) What are the four processes that make up the reversed Carnet cycle?

21) What is a cyclic process?

22) State alternative statements of the first law of thermodynamics?

23) Can you use the same plant as a heat pump in winter and refrigerator in summer?

Explain.

24) Show that COP of a heat Pump is greater than the COP of a refrigerator by Unity.

25) Establish the equivalence of Kelvin-Plank and Clausius Statements.

26) What is a reversible process? How is this be a limiting process?

27) All spontaneous processes are irreversible. Explain.

28) What are the causes of Irreversibility of a process.

29) Show that Heat Transfer through a finite temperature difference is irreversible.

30) Explain perpetual motion of the third kind.

31) Demonstrate using Second law how friction makes a process irreversible.

32) Explain the Carnot Heat Engine Cycle executed by (a) Stationary System (b) a

steady flow system.

33) What is a reversed heat engine?

34) Is the Third Law an extension of Second Law? Is it an independent Law of

nature ? Explain.

35) How does the efficiency of a reversible engine vary as the source and sink

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temperatures are varied? When does the efficiency become 100%?

36) What do you understand by Internal & external Irreversibility?

37) Explain Mechanical, Thermal and Chemical Irreversibilities.

38) A Carnot engine with a fuel burning device as source and a heat sink cannot be

treated as reversible plant.

39) Show that Entropy is a property of a system.

40) How entropy change of a reversible process is is estimated? Will it be different

for an irreversible process between the same end states?

41) Why Carnot Cycle on a T-S plot is a rectangle.

42) Giver the criteria of reversibility, irreversibility and impossibility of a

thermodynamic cycle.

43) What do you understand by the entropy principle?

44) When the system is in equilibrium, why would any conceivable change in entropy

is zero?

45) How did Rudolf Clausius summarize the first and second laws of

thermodynamics?

46) Show that transfer of heat through a finite temperature difference is irreversible.

47) What are the causes of Entropy Increase?

48) Why is an isentropic process not necessarily an adiabatic process?

49) What is the reversible adiabatic work for a steady flow system when K.E and P.E

changes are negligibly small? How is different from that for a closed stationary

system.

50) Why are the equations

T dS = dU + pdV

TdS= dH - vdP

Valid for any process between two equilibrium states.

51) What is the entropy generation in the isothermal and adiabatic dissipation of

work?

52) What do you understand by entropy transfer ? Why is entropy transfer associated

with heat transfer but not with work transfer?

53) What do you understand by high grade energy and low grade energy?

54) What is available energy and unavailable energy?

55) Who pronounced the concept of availability?

56) What is the available energy referred to a cycle?

57) What are Helmholtz Function and Gibbs Function?

58) What is the condition for exact differential?

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59) Derive Maxwell’s Equations.

60) Explain Absolute Entropy and Third Law of Thermodynamics.


UNIT – IV THERMODYNAMICS

1) What is a Pure Substance?

2) What do you understand by Saturation State?

3) What is triple point?

4) What is Critical state? Explain – Critical pressure, critical Volume of water and

Critical Temperature.

5) What is normal boiling point?

6) Draw Phase Diagram for a Pure substance on p-T Coordinates, T-s plot and h-s

plot.

7) Why do isobars on Moiller diagram diverge from one another?

8) Why do isotherms of Moiller diagram become horizontal in the super heated

region at low pressures?

9) Explain Degree of Superheat and Subcooling.

10) What is the quality of steam and what are the different methods of measurement

of quality.

11) Explain the principle of operation of electric calorimeter.

12) Derive Clausius-Clapeyron Equation.

13) Show that the slope of the sublimation curve at the triple point is greater than that

of the vaporization curve.

UNIT – V THERMODYNAMICS

1) What is Avogadro's law?

2) What do you understand by Saturation State?

3) What is the Equation of State?

4) What is fundamental property of gases with respect to product pv?

5) What is Universal Constant?

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6) Define an ideal gas.

7) Show that for an ideal gas, the internal energy depends only on its temperature.

8) Show that Enthalpy of an ideal gas is a function of temperature only.

9) What are different forms of energy and How does free expansion has zero work

transfer?

10) Why can't a throttling calorimeter measure the quality if the steam is very wet?

11) Define an ideal Gas.

12) What is Universal gas constant

13) What is an equation of state.

14) What is Boltzmann's Constant?

15) What is a poly tropic process?

16) Write down the Vanderwaals equation of state.

17) What are reduced properties.

18) What is Throttling ?

19) What is Free Expansion Process?

20) What is the generalized compressibility chart?

UNIT – VI THERMODYNAMICS

1. What is Avogadro's law

2. What do you understand by dry bulb temperatures?

3. What do you understand by wet bulb temperatures?

4. Define dew point temperature.

5. What is an adiabatic saturation process?

6. What do you understand by higher heating value and lower heating value of afuel?

7. Explain adiabatic flame temperature.

8. What is the proportion of oxygen and Nitrogen in atmospheric air on mass basis. 9.

What is the proportion of oxygen and Nitrogen in atmospheric air on Vol. basis. 10.

State third law of Thermodynamics

11. What is stoichiometric excess and deficient air?

12. Define dry ness fraction of steam.

13. Explain the process of steam generation.

14. Show the various stages during steam generation on P-V and T-S diagrams.

15. Define relative humidity.

]6. State Amagat's law of partial volumes.

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17. State Dalton's law of partial pressures.

18. What is meant by partial volume of constituent in a mixture.

19. What the relation between the partial pressure of vapor and the saturation pressureof water at the dew point temperature.

20. Define specific humidity of an air water vapor mixture.

21. What is meaning of partial pressure of a component in a mixture.

22. If one mole of mono-atomic gas is mixed with one mole of diatomic gas, whatwill be the molar heat capacity at constant volume for the mixture.

23. When do the DBT, WBT become equal?

24. What is Psychrometries?

25. What are hygroscopic materials?

26. What do you understand by saturated air and unsaturated air? 27.

What is degree of saturation?

28. What is psychrometer?

29. What is an adiabatic saturation process?

30. What is thermodynamic wet bulb temperature?31. What is the enthalpy of an air vapor mixture?32. Why does the enthalpy of an air vapor mixture remain constant during and

adiabatic saturation process.32. What is sensible heating or cooling?33. What is apparatus dew point?34. Write down the Carrier's equation?35. Which properties of air-water vapor mixtures are usually presented on a

psychrometric chart.36. Name the common reagent solutions used in Orsat apparatus and what purpose

does each reagent solution serve.37. What is meant by standard heat of a reaction?38. What is meant by theoretical air fuel ratio?39. Assume complete combustion, write down the combustion reaction for propane if

the required oxygen is supplied in the form of air?40. What is a cooling tower? How is it specified? Where is it used?

UNIT – VII THERMODYNAMICS

1) What is compression ration in 1. C Engines?2) Write the equation for efficiency of Carnot cycle3) State the four processes of the Carnot cycle.

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4) State the four process of Otto cycle.5) State the four process of diesel cycle.6) What is mean effective pressure.7) What is a mixed or duel cycle.8) What is a SJ Engine and how it differs form a C.l Engine.9) For the same compression ration and heat rejection which cycle is more efficient:10) Otto, Diesel or Duel.

11) What are cyclic and non cyclic heat engines? Give examples.

12) What is an air standard cycle.

13) Why are air standard cycles conceived?

14) What is the air standard cycle of S.I Engine?

15) What is a Compression ignition Engine?

16) Why is the compression ration of C.I Engine more than that of a S.I engine?

17) How is the compression ration of S.I engine fixed.

18) What is a combined cycle?

19) What is the application of closed cycle gas turbine plant?

20) What are the basic components of a gas turbine plant?

21) Define the cut-off ratio in a diesel cycle

22) Why is it possible to use higher compression ratio in the diesel cycle.

23) Why a certain class of heat engines are called internal combustion engines.24) In the Otto cycle, the combustion process is treated as & constant volume energy

Addition process. Explain why?25) Why the combustion of fuel in a diesel engine is assumed to occur at constant

pressure.

26) Draw the block diagram of a steam power plant.27) The thermal efficiency of the Otto cycle increases with increasing compression

ratio. To achieve higher efficiency is it possible to increase the compression ratio without any upper limit? Explain.

UNIT – VIII THERMODYNAMICS

1) What is refrigeration? How is ice and dry ice used for the purpose of

refrigeration?

2) What is Tonne of refrigeration?

3) Name a few refrigerants that are most widely used.

4) Show the block diagram of vapor compression refrigeration system

5) What are the expansion devices used in a vapour compression plant and when

they are used.

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6) Sketch the ideal vapor compression refrigeration cycle on a T -S diagram.

7) How is a reversed Brayton cycle used for refrigeration.

8) Why is the COP of gas cycle refrigeration system low?

9) Why is gas cycle refrigeration preferred in aircraft.

10) Define tonne of refrigeration.

11) Show the Bell-Coleman cycle on P- V and T -S diagrams.

12) Why is it not possible to operate a power plant on a Carnot cycle.

13) Why is it necessary to super heat the steam in the Rankine cycle?

14) Show Rankine cycle on P- V and T -S diagrams.

15) Why is COP of a gas cycle refrigeration low?

16) Why is gas cycle refrigeration system preferred in air craft?

17) What is absorption refrigeration cycle? Derive an expression for maximum COP

for this cycle.

18) What are the functions of analyzer and rectifier?

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