Section A:
(1) Attempt All The Questions: 5x2 = 10
a) Define system & surroundings.
b) What is heat pump & refrigerator?
c) What is availability?
d) What is Entropy?
e) What is triple point of water?
Section B:
(2) Attempt any three questions 3x5 = 15
(a) Distinguish between microscopic & macroscopic approaches of thermodynamics.
(b) What are the limitations of First law of thermodynamics? Explain the statements of Second law of thermodynamics.
(c) 2 kg of a gas at 10 bar expands adiabatically and reversibly till the pressure drops to 5 bar. During the process 120 kJ of non-flow work is done by the system, and the temperature falls from 377° centigrade to 257°C. Calculate the value of the index of expansion and the characteristics gas constants.
| Let the equation of expansion be P1-γ.Tγ = constant Hence, P1(1-γ)T1γ = P2(1-γ)T2γ |
(d) Derive the Tds equations.
(e) Steam at a pressure of 4 bar absolute and having dryness fraction of 0.75 is heated at constant volume to a pressure of 5 bar absolute. Find the final condition of the steam and the heat absorbed by 1 kg of steam.
Section C:
Attempt part (a) or part (b) of the following questions 5x5=25
(3) (a) Explain thermodynamic equilibrium and quasi-static process.
(b) A steam turbine developing 110 kW is supplied steam at 17.5 bar with an internal energy of 2600 kJ/min and specific volume of 0.155 m³/kg and velocity of 100 m/s. exhaust from turbine is at 0.1 bar with internal energy of 2093 kJ/min and sp. Volume = 15.5 m³/kg and velocity of 275 m/s. heat loss from the steam turbine 37.6 kJ/kg neglecting potential energy changes, determine steam flow rate in kg/hr.
(4)(a) Prove the equivalence of Kelvin-Planck statement & Clausius statement.
(b) A reversible engine takes 2400 kJ/min from a reservoir at 750 K develops 400 kJ/min of work during the cycle. The engine rejects heat to two reservoirs at 650 K & 550 K. Find the heat rejected to each sink.
(5)(a) Explain the principle of entropy increase.
(b) Explain the Gibbs Function & Gibbs free energy
(6)(a) Distinguish between Universal gas constant and characteristics gas constant with proper example.
(b) Explain the causes of internal and external irreversibility.
(7)(a) A gas having a moleculer mass of 28 occupies 0.13 m³ at a pressure of 1.5 bar and a temperature 21°C. Find the mass of gas and the volume as well as the density at 0°C and 1 bar pressure.
(b) One kg of an ideal gas is heated from 18.3°C to 93.4°C. Assuming R=287 J/kg-K and
γ = 1.18 for the gas. Find out (i) specific heats, (ii) change in internal energy and
(iii) change in enthalpy
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