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B3D087S Pages: 2

pump extracts 17kJ/s from 5°C reservoir. Determine (a) rate of heat supply from the
840°C source and (b) the rate of heat rejection to the 60°C sink. (6)

a) Establish the Inequality of Clausius? (4)

b) Two kg of air at 500 kPa, 80°C expands adiabatically in a closed System until
its volume is doubled and its temperature becomes equal to that of the surroundings
which is at 100 kPa, 5°C. For this process, determine (a) the maximum work, (b) the
change in availability and (€) the irreversibility. For air, take cy = 0.718 kJ/Kg K, ಟಿಎ
பே where cy is constant, and pV ಎ mRT where ற is pressure in kPa, V volume മന്‌, m

mass in kg, R a constant equal to 0.287 kJ/kg K, and T temperature in K. (6)
a) Explain mollier chart, P-V, P-T, P-V-T diagrams for pure substances. (7)
b) A domestic food freezer maintains a temperature of -150C. The ambient air

temperature is 300C. If heat leaks into the freezer at the continuous rate of 1.75KJ/S
what is the least power necessary to pump this heat out continuously? (3)

a) What is energy, dead state and triple point? (4)
b) A rigid vessel contains | kg of a mixture of saturated water and saturated steam
at a pressure of 0.15 MPa. When the mixture is heated, the state passes through the
critical point. Determine (i) The volume of the vessel (ii) The mass of liquid and of
vapour in the vessel initially(iii) The temperature of the mixture when the pressure has
risen to 3 MPa (iv) The heat transfer required to produce the final state. (6)
PART 0
Answer any FOUR questions.

Derive Maxwell relations from basic thermodynamic relations? (10)

. a) Write down the van der Waals equation of state. How does it differ from the ideal
gas equation of state? (4)
b) Express the changes in internal energy and enthalpy of an ideal gas in a reversible
adiabatic process in terms of pressure ratio. (6)
Explain different properties of real gas mixtures and the laws associated. (10)
a) Define adiabatic flame temperature. How is it estimated? (5)
b) What is enthalpy of combustion? What do you understand by higher heating value
and lower heating value of fuel? ⋅ (5)
a) Derive TDS Equations (4)

b) A supply of natural gas is required on ೩ site 800 m above storage level. The gas 8 -
150°C, 1.1 bar from storage is pumped steadily to a point on the site where its
pressure is 1.2 bar, its temperature 15°C, and its flow rate 1000 113 /hr. If the work
transfer to the gas at the pump is 15 kW, find the heat transfer to the gas between the
two points. Neglect the change in K.E. and assume that the gas has the properties of
methane (CH4 M=16) which may be treated as an ideal gas having y = 1.33 (£ = 9.75

m/s?) (6)

a) Derive Clausius clapeyron equation. (6)

0) A certain gas has Pc = 0.913 and V c= 0.653 kJ/kg K. Find the molecular weight

and the gas constant R of the gas. (6)
ROKK

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