Winter 2016 Thermodynamics Question Paper

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GUJARAT TECHNOLOGICAL UNIVERSITY
DIPLOMA ENGINEERING – SEMESTER – 3 • EXAMINATION – WINTER - 2016
Subject Code: 3331902 Date: 22-11-2016
Subject Name: Thermodynamics
Time: 10:30 am to 01:00 pm Total Marks: 70

Instructions:
1. Attempt all questions.
2. Make Suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. Use of programmable & Communication aids are strictly prohibited.
5. Use of only simple calculator is permitted in Mathematics.
6. English version is authentic.

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Q.1 Answer any seven out of ten.  14

1. State concept of air standard cycle.

2. List four types of system.

3. Define enthalpy and entropy.

4. Write four conditions for steady flow.

5. Represent isothermal process on P-V and T-S diagram.

6. Define heat engine and refrigerator.

7. Define ideal gas and throttling process.

8. State two applications of Carnot cycle.

9. Write equation of COP for reversed brayton cycle

10. Define process and cycle.

Q.2 (a) Classify system boundaries and give two examples of each type. 03

OR

(a) Differentiate point function and path function. 03

(b) Derive expression for work done during isentropic process. 03

OR

(b) Explain characteristics of gas constant (R). 03

(c) State and explain limitations of first law of thermodynamics. 04

OR

(c) Write full form of SFEE and apply SFEE Equation for steam engine. 04

(d) 10 kg air enters into a nozzle with negligible velocity. Its pressure reduces from 392.4
kPa to 196.4 kPa during the flow from the nozzle and temperature reduces from 9500C
to 7600C during the flow. Find velocity of air at exit. Take γ = 1.395, Cp = 1.005 KJ/Kg,
Cv= 0.72 KJ/Kg, and R = 0.285 kj/kgK. 04

OR

(d) Air has initial volume 0.6 m3, pressure 60 N/cm2 and temperature 900C. It is expanded isothermally up to pressure 15 N/cm2. Find work done and change in internal energy and
mass. Take R= 0.287 KJ/Kg K. 04

Q.3 (a) Explain specific heat at constant pressure (Cp). 03

OR

(a) One kg of gas enclosed in a closed vessel has absolute pressure 2 bar and temperature
 270C. If it is compressed up to 5 bar pressure, find 1] final temperature 2] change in
 internal energy. Take Cp = 1.005 KJ/Kg K and R = 0.297 KJ/KgK. 03

(b) Derive Cp – Cv = R with usual notations. 03

OR

(b) Derive equation of work done in polytropic process. 03

© In one otto cycle engine clearance volume is 30% of its swept volume. Find
air standard cycle efficiency if γ = 1.4. 04

OR

(c) Draw the dual cycle on P–V and T-S diagram and write the equation of air
standard efficiency of dual cycle. 04

(d) Classify thermodynamics cycles. 04

OR

(d) Draw the diesel cycle on P–V and T-S diagram and explain its processes. 04

Q.4 (a) A closed system executes adiabatic process due to which a change in internal energy
takes place. A work of 10 kJ is done by the system on surroundings during this process.
Determine change of specific internal energy of the system if system contains mass of 0.2 kg. 03

OR

(a) What is entropy and explain its importance in thermodynamics. 03

(b) A refrigerator keeps vegetables at temperature 100C by removing 50 kJ heat
from it. If it rejects 75 kJ heat into the atmosphere find its C.O.P. and work required. 04

OR

(b) A heat engine takes 10000 kJ/hr heat energy from source of temperature 3270C and rejects
5000 kJ/hr heat into sink of 270C temperature. Find out its thermal efficiency and decide
whether this heat engine is reversible one or irreversible one. 04

(c) Derive equation for air standard efficiency of otto cycle. 07


Q.5 (a) One gas turbine works on Brayton cycle between 5 bar and 1 bar pressure.Find air standard efficiency. Take γ = 1.4. 04

(b) Prove that entropy is a point function. 04

(c) Define 1] Boyle’s law 2] Charle’ law 3] Reunault’s law. 03

(d) Differentiate reversibility and irreversibility. 03

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Summer 2016 Thermodynamics Question Paper

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GUJARAT TECHNOLOGICAL UNIVERSITY
DIPLOMA ENGINEERING – SEMESTER – III• EXAMINATION – SUMMER 2016
Subject Code: 3331902 Date: 17/05/2016
Subject Name: Thermodynamics
Time: 02:30 PM TO 5:00 PM Total Marks: 70

Instructions:
1. Attempt all questions.
2. Make Suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. Use of programmable & Communication aids are strictly prohibited.
5. Use of only simple calculator is permitted in Mathematics.
6. English version is authentic.

*************

Winter 2015 Thermodynamics Question Paper

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GUJARAT TECHNOLOGICAL UNIVERSITY
DIPLOMA ENGINEERING – SEMESTER – III • EXAMINATION – WINTER 2015
Subject Code: 3331902 Date: 04- 12- 2015
Subject Name: Thermodynamics
Time: 10:30 AM TO 01:00 PM Total Marks: 70

Instructions:
1. Attempt all questions.
2. Make Suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. Use of programmable & Communication aids are strictly prohibited.
5. Use of only simple calculator is permitted in Mathematics.
6. English version is authentic.

************

Q.1 Answer any seven out of ten. 14

1. Explain cut-off ratio.

2. List types of boundary.

3. Define enthalpy and write its unit in S.I. system.

4. Write steady flow energy equation.

5. Represent isentropic process on P-V and T-S diagram.

6. Write statement of Boyle’s law and Charle’s law.

7. Write concept of reversibility and irreversibility of thermodynamics.

8. State application of Otto cycle.

9. Write equation of COP for reversed brayton cycle.

10. Define heat and work.

Q.2 (a) Define thermodynamic system with example. 03

OR

(a) Explain how SFEE is applied to turbine. 03

(b) Derive expression of work done during isothermal process. 03

OR

(b) Explain universal gas constant (Ru). 03

(c) Prove that internal energy is a point function. 04

OR

(c) Explain first law of thermodynamics with help of joule’s experiment. 04

(d) In a gas turbine, air enters with velocity 220 m/s and enthalpy 5678 KJ/Kg with steady mass flow rate of 3.6 Kg/Sec. Gas exits from the system at velocity 170 m/s and enthalpy 4560 KJ/Kg. If 54 KJ/Kg heat is wasted into the surroundings, find power developed by the gas turbine. 04

OR

(d) 2 kg. of gas enclosed in a closed vessel heated from 2 bar to 5 bar. The initial temperature of gas is 27oC. Find 1] final temperature 2] change in internal energy. Take Cv = 0.72 KJ/Kg K. 04

Q.3 (a) Derive characteristics equation for ideal gas. 03

OR

(a) Draw P-V and T-S diagram for... (1) Isobaric process (2) Isochoric process. 03

(b) Derive Cp - Cv = R with usual notations. 03

OR

(b) Derive equation of work done in isentropic process. 03

(c) In an engine, working on diesel cycle, compression ratio is 15 and fuel is cut off at 5% of stroke length, find air standard efficiency. Take γ = 1.4 04

OR

(c) Draw the diesel cycle on P-V and T-S diagram and write the equation of air standard efficiency of diesel engine. 04

(d) Differentiate process and cycle. 04

OR

(d) Draw the dual cycle on P-V and T-S diagram and explain its processes. 04

Q.4 (a) Derive general energy equation for first law of thermodynamics. 03

OR

(a) Derive equation of COP for reversed Carnot cycle for refrigeration purpose. 03

(b) Deduce the equivalence between Kelvin-plank and clausius statements at second law of thermodynamics on the basis of diagrammatic representation. 04

OR

(b) One Carnot engine receives 1200 KJ/min heat energy from the reservoir of 350oC temperature and rejects heat energy to the sink of 25oC temperature. Find thermal efficiency and work done. 04

(c) Derive equation for air standard efficiency of brayton cycle. 07

Q.5 (a) In one Otto cycle engine clearance volume is 30% of its swept volume. Find air standard cycle efficiency. Take γ = 1.4 04

(b) Define 1] heat engine 2] heat source 3] refrigerator 4] heat reservoir. 04

(c) Define. 1] Specific heat at constant pressure (Cp) 2] specific heat at constant volume (Cv). 03

(d) State limitations of first law of thermodynamics. 03

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Summer 2015 Thermodynamics Question Paper

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GUJARAT TECHNOLOGICAL UNIVERSITY
Diploma Engineering - SEMESTER–III • EXAMINATION – SUMMER • 2015
Subject Code: 3331902 Date: 06-05-2015
Subject Name: Thermodynamics
Time: 02:30 pm - 05:00 pm Total Marks: 70

Instructions:
1. Attempt all questions.
2. Make Suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. Use of programmable & Communication aids are strictly prohibited.
5. Use of only simple calculator is permitted in Mathematics.
6. English version is authentic.

************

Q.1 Answer any seven out of ten. 14

1. Define pressure and its units in SI system.

2. Differentiate heat &work.

3. Differentiate thermodynamic cycle and mechanical cycle.

4. Explain closed system with sketch.

5. Write statement of zeroth law of thermodynamics.

6. Give examples of reversible process.

7. Define system and surroundings.

8. Write first law of thermodynamics for cyclic process.

9. Explain cut-off ratio.

10. Define thermal efficiency of heat engine.

Q.2 (a) A system contains 10Kg of a gas. During a process 15 KJ work is done on the system
& 40KJ heat rejected from the system. Find change of specific internal energy of the system. 03

OR

(a) If a system expands from 1m3 Volume to 4m3Volume at constant pressure. 10 bar.
Find boundary work during the process. 03

(b) Apply steady flow energy equation to nozzle. 03

OR

(b) Apply steady flow energy equation to boiler. 03

(c) With help of joule experiment explain first law of thermodynamics. 04

OR

(c) Prove that internal energy is a point function. 04

(d) Define (i) heat engine (ii) refrigerator (iii) heat pump (iv) entropy. 04

OR

(d) Represent Carnot cycle on P-V and T-S diagram and explain its processes. 04

Q.3 (a) Draw following process on P-V and T-S diagram.
(i) constant pressure process (ii) isothermal process. 03

OR

(a) Define (i) specific heat at constant pressure (CP) (ii)specific heat at constant volume(CV). 03

(b) Explain universal gas constant (Ru) & write is mathematical relation with characteristic gas constant(R)with example. 03

OR

(b) Explain Boyle’s law with neat sketch. 03

(c) Air of initial volume 0.1m3& pressure 1.5bar absolute pressure is expanded up to final
volume 0.6m3 Isothermally. Find (i) final absolute pressure (ii) heat transfer during process. 04

 OR

(c) 1 kg of gas enclosed in a closed vessel has absolute pressure 2 bar & temperature 30o C. If it is compressed up to 6 bar pressure find (i)final temperature & (ii)Change in internal energy.
Take CP =1.005 kJ/kgk & gas constant R=0.287 kJ/kgk. 04

(d) Derive characteristic equation for ideal gas. 04

OR

(d) Represent diesel cycle on P-V& T-S diagrams and explain its processes. 04

Q.4 (a) Differentiate power producing cycle and power absorbing cycle. 03

OR

(a) State limitations of first law of thermodynamics. 03

(b) Explain Kelvin Plank statement of second law of thermodynamics with neat sketch. 04

OR

(b) Gas turbine works on brayton cycle between 6bar &1bar pressure find air standard efficiency. Take γ=1.4 04

(c) Derive equation of air standard efficiency of an Otto cycle. 07

Q.5 (a) Explain thermodynamic equilibrium. 04

(b) Prove that CP - CV=R. 04

(c) Prove that (C.O.P)Heat pump = (C.O.P)Refrigerator + 1. 03

(d) Differentiate process and cycle. 03

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Winter 2014 Thermodynamics Question Paper

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GUJARAT TECHNOLOGICAL UNIVERSITY
DIPLOMA ENGINEERING – SEMESTER –III EXAMINATION – WINTER 2014
Subject Code: 3331902 Date: 29/11/2014
Subject Name: Thermodynamics
Time: 10:30 am – 1:00 pm Total Marks: 70

Instructions:
1. Attempt any five questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. Each question carry equal marks (14 marks)

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Q.1 (a) Explain Quasi-static process with neat sketch and diagram. 07

(b) (1) Define energy. Write the similarities and differences of heat energy and work energy.
(2) Explain Avogadro’s law. 04

Q.2 (a) In gas turbine mass flow rate of gas is 5Kg/s. The velocity of air at entrance is 200m/s and
its enthalpy is 6600 KJ/Kg. The velocity of outgoing gas is 150m/s and its enthalpy is 5500KJ/Kg. Heat rejected from the system to surrounding is 50KJ/Kg. Determine power developed by the
turbine. 07

(b) Explain control mass and control volume. Explain application of SFEE. 07

OR

(b) Explain how first law of thermodynamics is applied to Boiler & turbine to
energy transfer. 07

Q.3 (a) For an adiabatic process prove that pvγ = constant. 07

(b) In a gas turbine expansion of the gas take place from 10 bar pressure to 1 bar
pressure. During the expansion change in volume is from 2m3 to 8m3.Find out
value of polytropic index n and workdone of the process. 07

OR

Q.3 (a) Draw and explain polytropic and isothermal process on P-V and T- S diagram. 07

(b) 0.1 m3 of air at a pressure of 1.5 bar is expanded isothermally to 0.5m3.
Calculate the final pressure of the gas and heat supplied during process. 07

Q.4 (a) Explain Kelvin plank statement. Prove equivalence between Kelvin plank and
Clausius statement. 07

(b) Explain International Practical Temperature Scale. 07

OR

Q. 4 (a) What is Entropy ? Explain its importance in thermodynamics. 07

(b) Explain the C.O.P of refrigerator, Heat pump and thermal efficiency of heat engine. 07

Q.5 (a) Derive the expression of air standard efficiency of otto cycle. 07

(b) An engine working on otto cycle is supplied with air at 0.1 Mpa,300c the compression ratio is 5. Heat supplied is 2000 KJ/Kg. Calculate the maximum pressure,temperature of the cycle and the
 cycle efficiency. Take Cp =1.005KJ/Kg K,Cv = 0.718 KJ/Kg K, R = 0.287 KJ/Kg K. 07

OR

Q.5 (a) Derive the expression of air standard efficiency of Dual cycle. 07

(b) In Diesel cycle the compression ratio is 16, pressure and temperature in begining of the compression stroke are 1 bar & 20 0C respectively and the maximum temperature of the cycle is 1430 0C. Find the thermal efficiency of cycle. 07

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Summer 2014 Thermodynamics Question Paper

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GUJARAT TECHNOLOGICAL UNIVERSITY
Diploma Engineering - SEMESTER–III • EXAMINATION – SUMMER • 2014
Subject Code: 3331902 Date: 17-06-2014
Subject Name: Thermodynamics
Time: 10:30 am - 01:00 pm Total Marks: 70

Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. English version is considered to be Authentic.

************

Q.1 (a) Define Thermodynamic system with example and enlist the thermodynamic properties. 07

(b) Define system Boundary, Classify system boundaries with suitable example. 07

Q.2 (a) Explain first law of thermodynamics with the help of Joule’s experiment. 07

(b) Classify energy and explain internal energy. 07

OR

(b) Explain how SFEE is applied to Air compressor, Turbine and Nozzle for energy transfer. 07

Q.3 (a) State Kelvin Plank and Clausius statement of second law of thermodynamics
and show their equivalence with sketch. 07

(b) An inventor claims that his engine takes 150000J at temperature 270C and rejects 50000 J at temperature -230C and delivers 30kWh work. Is his engine is theoretically possible?  07

OR

Q.3 (a) Explain Reversible and irreversible processes with example. 07

(b) Define following
(1)Heat Source (2) Heat Sink (3) Heat Pump (4) Heat Engine. 07

Q.4 (a) Draw different process of ideal gas on P-V and T-S diagram. 07

(b) One kg of air at 3.5 bar and 1770C expands adiabatically to a pressure of 1.3 bar. Calculate the amount of external work done and change in internal energy of air during expansion.
Take R= 278J/kg0K and γ = 1.4 07

OR

Q. 4 (a) Define specific heat at constant volume and specific heat at constant pressure
and state the relationship. 07

(b) During Isothermal process the 1.5 kg of air compressed from 1bar and 200C temperature to a pressure of 5bar. Calculate the amount of external work done, heat transfer and change in internal energy. Take R= 278J/kg0K and γ = 1.4 07

Q.5 (a) Draw the Diesel cycle on P-V and T-S diagram and write the equation of air
standard efficiency. 07

(b) Derive the expression for air standard efficiency of Otto cycle. 07

OR

Q.5 (a) State the limitation of air standard cycle. 07

(b) Engine working on Diesel cycle the compression ratio is 16 and fuel is cut off at 5% of stroke length. Find out air standard efficiency. Take γ= 1.4 07

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Winter 2013 Thermodynamics Question Paper

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GUJARAT TECHNOLOGICAL UNIVERSITY
Diploma Engineering - SEMESTER–III • EXAMINATION – WINTER 2013
Subject Code: 3331902 Date: 30-11-2013
Subject Name: Thermodynamics
Time: 02:30 pm - 05:00 pm Total Marks: 70

Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. English version is considered to be Authentic.

************

Q.1 (a) State the Zeroth law of thermodynamics and its application. Name various
Temperature measurement devices used with related unit. 07

(b) Differentiate followings
(1) Heat and Work. 03
(2) Extensive properties and Intensive properties. 02
(3) Thermodynamic cycle and Mechanical cycle. 02

Q.2 (a) State first law of thermodynamics and prove internal energy is a property. 07

(b) Which are the conditions for steady flow? Derive SFEE for open system. 07

OR

(b) State both statement of second law of thermodynamics. Also show their
equivalence with neat sketch. 07

Q.3 (a) A heat engine receives energy of 2000 kJ/min and doing work of 1500 kJ/min.
Find out thermal efficiency and heat rejection rate. 07

(b) Derive characteristic of gas equation using an ideal gas laws. 07

OR

Q.3 (a) 2 kg of gas enclosed in a closed vessel has absolute pressure 2 bar and temperature 27 °C. If it is compressed up to 6 bar pressure find Temperature and change in internal energy.
Take Cp=1.005 kJ/kg K, R = 0.287 kJ/kg K. 07

(b) Draw P-V and T-ϕ diagram for Isothermal process and derive equation of
work and heat for Isothermal process. 07

Q.4 (a) Show following process on P-V and T-S plane
(1) Constant volume Process (2) Isothermal Process.
(3) Isentropic Process (4) Isobaric Process. 07

(b) Derive equation of C.O.P. for reversed Brayton cycle for refrigeration purpose. 07

OR

Q. 4 (a) Explain the term Entropy. Discuss the practical significance of entropy. 07

(b) A Compression Ignition Engine working between 60 °C and 800 °C. What
could be the maximum efficiency of the cycle? 07

Q.5 (a) Explain following
1. Concept of Air standard efficiency. 03
2. Name the methods of measuring dryness fraction of steam. 04

(b) In a refrigerator working on reverse Brayton cycle, air is compressed from 10°C and 1 bar pressure to 5 bar pressure. After compression air is cooled down to 20 °C in air cooler,
Find (1) C.O.P. (2) work required. Take Cp = 1.005 kJ/kg K, Cv = 0.718 kJ/kg K. 07

OR

Q.5 (a) Define followings : (1) Wet steam (2) Dry and Saturated steam  (3) Sensible heat
(4) Triple point (5) Degree of super heat (6) Dryness fraction steam (7) Latent heat. 07

(b) Determine the enthalpy, entropy and volume for 5 kg of steam having 12 bar
pressure and 0.85 dryness fraction. 07

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Thermodynamics previous year question paper | 3331902 |

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