engineering thermodynamics question bank

ME 2202- ENGINEERING THERMODYNAMICS

QUESTION BANK

UNIT-I

BASIC CONCEPT & FIRST LAW

PART –A (2 marks)

1. Define the term thermal engineering.

2. What is meant by thermodynamics system? How do you classify it?

3. What is meant by closed system? Give an example.

4. Define an open system Give an example.

5. Distinguish between Open and Closed system

6. Define an isolated system:

7. Define specific heat capacity at constant pressure.

8. Define specific heat capacity at constant volume.

9. What is meant by surroundings?

10. What is boundary?

11. What is meant by thermodynamic property

12. How do you classify the property?

13. Define Intensive and Extensive properties.

14. What do you understand by equilibrium of a system?

15. Differentiate Intensive and Extensive properties

PART –B

1. one kg of gas expands at CO&11stant pressure from 0.085 m3 to 0.13 Ill).if the initial

temperature of the gas is 22.5 °c. find the final. Temperatures, net heat transfer, change in

internal energy, pressure of gas. (16)

2. A certain quantity of gas is head at constant pressure from 35 °0 to 185°c. Estimate the

amount of hem transferred, ideal work done, change in internal energy, when the initial volume of

the gas is 0.6 m3. (16)

3. Explain and derive Isothermal process (16)

4. Explain and derive Isobaric process. (16)

5. 2kg of gas at a pressure of 1.5 bar. Occupies a volume of 2.5 m3. If this gas compresses

isothermally to 1/3 times the initial volume. Find initial. Final temperature, work done, heat

transfer. (16)

6. one kg of air is compressed polytropically (n=1.3) from 1 bar and 27 deg Celsius

to 3 bar. Find I. work transfer , 2.Heat transfer,3. Change in internal energy (16)

UNlT-2

SECOND LAW

PART –A (2 marks)

1. State the Kelvin - Planck statement of second law of thermodynamics.

2. State Clausius statement of second law of thermodynamics.

3. Write the two statements of the Second law of thermodynamics.

4. State Carnot's theorem.

5. What are the Corollaries of Carnot theorems?

6. Define - PMM of second kind.

7. What is difference between a heat pump and refrigerator?

8.What is mean by heat engine?

9. Define the term COP.

10. Why Carnot cycle cannot be realized in practice?

11. Name two alternative methods by which the efficiency of a Carnot cycle can be increased.

12. Why a heat engine cannot have 100% efficiency

13. When the Carnot cycle efficiency will be maximum?

14. What are the processes involved in Carnot cycle

PART –B

1. Air flows through an adiabatic compressor at 3 kg/s the inlet conditions are 2 bar and 310k

and exit conditions are 20 bar and 560 k. compute the net rate of availability transfer and

irreversibility. (16)

2. Air in a closed vessel of fixed volume of 0.15 m 3, exerts pressure of 12 bar at 250 °c ,if the

vessel is cooled so that the pressure falls to 3.5 bar, determine the final temperature, heat

transfer and change of entropy. (16)

3. Explain Carnot engine cycle and its efficiency. (16)

4. Explain the term availability and unavailability. (16)

5. A heat engine operates between a source a 600 °c and a sink at 60 c Determine the least rate

of heat rejection per KW net output of the engine. (16)

6. 0.2 kg of air at 1.5 bar and 27 "c is compressed to a pressure of 15 bar according to the law

pv (l.25) =c. determine work done heat flow to or from the air, increase or decrease in entropy

(16)

UNIT- 3

PROPERTIES OF PURE SUBSTANCE & STEAM POWER CYCLE

PART –A (2 marks)

1.Define latent heat of ice.

2. What is pure substance?

3. What is saturation temperature and saturation pressure?

4. Define latent Heat of vaporization.

5. Find the saturation temp and latent heat of vaporization of steam at 1 Mpa.

6. Define the terms 'Boiling point' and 'Melting point .

7. What is meant by super heated steam and indicate its use.

8. Define: sensible heat of water.

9. Define the term "Super heat enthalpy".

10. What are wet and dry steam?

11 State phase rule of pure substances.

12. Define dryness fraction of steam (or) What is quality of steam?

13. Explain the terms: Degree of super heat, Degree of sub cooling.

14. Define triple point and critical point for pure substance.

PART –B

1. Find the specific volume and enthalpy of steam at 9 bar when the condition of steam is

a) Wet with dryness fraction 0.95 b) dry saturated c) super heated temperature of 240° (16)

2. Steam initially at 400 Kpa and 0.6 dry is heated in a rigid vessel of 0.1m3 volume. The final

condition is 600 Kpa. Find the amount of heat added and mass of steam. (16)

3. Explain P-V diagram and P-V-T surface. (16)

4. 2 kg of steam initially at 5 bar and 0.6 dry is heated at constant pressure until the temperature

becomes 350 c.find the change in entropy and internal energy. (16)

5.A steam plant working on a simple rankine cycle operated between the temperature of 260°c

and 95°c .the steam is dry and saturated when it enters the turbine and expanded isentropic ally.

Find rankine efficiency. (16)

6) 2.5 kg of steam is heated at constant pressure of 250 kpa and 100°c, until temperature is

250°c. Find the amount of heat added and change in entropy. (16)

(Use mollier chart)

UNIT – 4

IDEAL AND REAL GASES AND

THERMODYNAMIC RELATION

PART –A (2 marks)\

1. Determine the molecular volume of any perfect gas at 600N/m2 and 300 C. Universal gas

constant may be taken as 8314J/kg mole-K.

2. State Boyle's law.

3. State Charle's law.

4. State Joule's law.

5. State Regnault's law.

6. State Avogadro's law.

7. State Dalton's law of partial pressure

8. How does the Vander Waals equation differ from the ideal gas equation of state?

9. What is meant by virtual expansion?

10. Distinguish between ideal and real gas.

11. Define Joule-Thomson Co-efficient.

12. Define Co-efficient of volume expansion and Isothermal compressibility.

13. What is compressibility factor?

14. What is compressibility factor? What does it signify? What is its value for an ideal gas at

critical point?

PART –B

.1. Derive Dalton’s law of partial pressure. Define amagats law of partial volume. (16)

2. Derive vandar Waals equation. (16)

3. Derive Maxwell’s equation (16)

4. Derive clausius-clapeyron equation. (16)

5. Derive Joule-Thomson coefficient equation. (16)

6. A mixture of gases contains 50%nitrogen,40% oxygen and 10% carbon di oxide by mass. 2

kg of mixture is compressed from 200 kpa and 293k to 400 kpa polytropically which follows

the PV(I.25)=C. Determine the work done, heat transferred and change in entropy.

(Take (cp)n2=1.04 (cp)o2= 0.918 kj / kg k, (cp)co2=O.846 k/k (16)

UNIT – 5

PSYCHROMETRY

PART –A (2 marks)

1. What is the difference between air conditioning and refrigeration?

2. Define psychrometry.

3. Define dry bulb temperature (DBT).

5. Define wet bulb temperature.

6. Define dew point temperature.

7. Define Relative Humidity (RH) and Specific humidity'.

8. Differentiate between absolute and relative Humidity.

9. Define DPT and degree of saturation.

10. What is dew point temperature? How is it related to dry bulb and wet bulb temperature at the

saturation condition?

11. Define Apparatus Dew Point (ADP) of cooling coil.

12. List down the psychrometirc processes.

13. Define bypass factor (BPF) of a coil.

14. State the effects of very high and a very low bypass factor.

15. What are the assumptions made while mixing two air streams

PART –B

I. Dry bulb and wet temperatures of 1 atmospheric air stream are 40°0 and 30°c

respectively. Determine

(a)Humidity (b) Relative humidity (c) Specific humidity. (16)

2. Atmospheric air with barometric pressure of 1.013 bar has 38°c dry bulb temperature

and 28°c wet bulb temperature. Determine (a) Humidity ratio (b) Relative humidity (c) dew

point temperature. (16)

3. Atmospheric air at 760 mm of Hg has 45°c DBT and 30°c WBT, using psychometric

chart calculate R.H, Humidity ratio, DPT, enthalpy, specific volume of air. (16)

4.Atmospheric air at 1 bar pressure has 2.5°0 DBT and 75% RH using psychometric chart,

calculate DBT, enthalpy, vapour pressure. (16)

5. Explain sensible heating process, sensible cooling, and humidification process. (16)

6. An air water vapour mixture at 0.1 Mpa, 30°0, 80% RH. Has a volume of 50 m3

Calculate the specific humidity, dew point, wet bulb temperature, mass of dry air and mass of

water vapour. (16)

7.Calculate the specific humidity, dew point, wet bulb temperature, mass of dry air and mass of

water vapour. (16)