Q.1
14 Marks(a)
Define the terms:
1)Thermodynamics System
2)Property
3)Cycle
(b)
Explain thermodynamic equilibriumbriefly.
(c)
Derive S.F.E.E. clearly stating assumptions. Reduce it for turbine.
Gujarat Technological UniversitySummer 2025 examination
GTU 3131905 Engineering Thermodynamics Summer 2025 Question Paper & PDF
B.E. · Mechanical Engineering · Semester 3 · Subject code 3131905
- Total
- 70 marks
- To pass
- 23 marks (33%)
- Duration
- 2.5 Hours 2:30 PM – 5:00 PM
- Questions
- 5 with internal choice
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5 of 25 questions on this paper were also asked in other years. 2 more are types of question GTU sets again with new data. Each is marked below with the years it appeared.See all 7 repeated 3131905 questions, most asked first
Q.2
14 Marks(a)
Show that the COP of a heat pump is always greater than the COP of refrigerator.
(b)
Explain PMM of kind I and II.
(c)
Steam enters a nozzle at 7 bar pressure and 20⁰ C (initial enthalpy = 2850 kJ/kg) and leaves at a pressure of 1.5 bar. The initial and final velocities of steam is 40 m/s nad 700 m/s respectively throught the nozzle. The mass flow rate is 1400 kg/hr and heat loss from the nozzle is 11705 kJ/hr. Specific volume at exit is 1.24 m³/kg.Determine final enthalpy and exit area.
OR
(c)
An inventor claims that his engine developes 75 kW of power while operating between 1023K and 298K temperature. The amount of fuel(C.V. of fuel = 74500 kJ/kg) burnt per hour is 3.9 kg. Comment about the validity of his claim and justify your comment.
Q.3
14 Marks(a)
State and prove Clausius theorem.
(b)
Show that efficiency of a reversible heat engine operating between two constant temperatures is maximum.
(c)
A block of 100 kg of iron at temperature 100⁰C is immersed in 50 kg of water at a temperature of 20⁰C. Determine the entropy change for combined system of iron and water. Take Cp of iron and water as 0.42 kJ/kgK and 4.18 kJ/kgK respectively.
Also asked in Summer 2026 Q5c OR
OR
(a)
Define:
i)Availability
ii)Irreversibility and
iii)Dead state.
(b)
Explain Guoy-Stodola theorem.
(c)
Explain principle of increase of entropy. Apply it for the heat transfer through a finite temperature difference.
Also asked in Summer 2026 Q5c
Q.4
14 Marks(b)
For the same compression ratio and heat rejection, compare Otto, Diesel and Dual cycle. Explain with p-v and T-s diagram.
(c)
Draw Rankine cycle on P-v, T-s and h-s diagrams and derive an expression for its thermal efficiency with and without pump work.
Also asked in Summer 2026 Q3c OR
OR
(b)
Explain simple regenerative Rankine cycle.
(c)
A diesel engine has compression ratio of 20. The compression begins at 0.1 MPa and 35⁰C. The heat added is 1700 kJ/kg. Calculate maximum pressure and temperature of cycle, work done per kg of air and cycle efficiency.
Also asked in Summer 2026 Q3c
Q.5
14 Marks(a)
Define the following terms related to combustion process:
i)HCV
ii)LCV
iii)Enthalpy of formation
(c)
Discuss factors affecting performance of VCR cycle.
OR
(a)
Explain Stoichiometric air fuel ratio in detail.
(b)
Calculate the amount of theoretical air required for the combustion of 1 kg of acetylene (C2H2) to CO2 and H2O.
(c)
In a steam power cycle, the dry saturated steam supplied at 15 bar. The condenser pressure is 0.4 bar. Calculate the Carnot and Rankine efficiencies of the cycle. Neglect pump work.
More Engineering Thermodynamics papers
Questions repeat across sessions. Working through two or three papers shows you which topics GTU asks most.
Other Semester 3 subjects
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About this paper
Official Gujarat Technological University (GTU) examination paper for Engineering Thermodynamics (Summer 2025, B.E. · Mechanical Engineering, Sem 3). Features complete 70-mark regular & remedial examination pattern, official marking distribution across all 5 questions, and direct 1-click official PDF download.
Transcribed for student exam preparation from Gujarat Technological University official examination archives. Questions, syllabus guidelines, and curriculum marking schemes remain the intellectual property of Gujarat Technological University.