STUPIDSID
Answer any Five of the following:
1 (a)
State the first law of thermodynamics for the Closed system undergoing a cycle.
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1 (b)
Explain Zeroth Law of Thermodynamics.
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1 (c)
Show that entropy is property of system.
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1 (d)
Define Availability and Unavailability.
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1 (e)
Define COP for refrigerator and heat pump. Derive relation between them.
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1 (f)
Define:
i) Dryness Fraction
ii) Sensible heat of water
iii) Latent heat of vaporisation
iv) Superheated Steam.
i) Dryness Fraction
ii) Sensible heat of water
iii) Latent heat of vaporisation
iv) Superheated Steam.
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2 (a)
State the Kelvin Planck and Clausius statement and establish the equivalence of both for Second law of Thermodynamics.
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2 (b)
One kg of dry saturated steam undergoes an isentropic expansion process from 10 bar to
i) In a cylinder fitted with a piston
In a turbine.
i) In a cylinder fitted with a piston
In a turbine.
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3 (a)
State and derive Steady flow energy equation and apply it to a boiler, condenser, nozzle and turbine.
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3 (b)
Liquid Octane C8 H18 at 25°C is used as fuel. Air used is 150% of theoretical air and is supplied at 25°C. Assume a complete combustion and the product leaves the combustion chamber at 1600K. Calculate heat transfer per kg mole of fuel. Use the following data
| Substance | h°f (MJ/Kmole) | h298K (MJ/Kmole) | h1600K (MJ/Kmole) |
| C8H18 | -250 | - | - |
| O2 | - | 8.68 | 52.96 |
| N2 | - | 8.67 | 50.57 |
| H2O (gas) | -241.8 | 9.9 | 62.75 |
| CO2 | -393.5 | 9.36 | 76.95 |
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4 (a)
Derive an expression for efficiency of Diesel cycle.
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4 (b)
A mass of air initially at 206°C is at a pressure of 7bar and has a volume of 0.03m3. The air is expanded at constant pressure to 0.09m3, a polytrophic process with n=1.5 is then carried out, followed by a constant temperature process which completes the cycle. All the processes are reversible. Sketch the cycle on pressure-volume diagram and find the heat received and heat rejected in the cycle.
Take R=0.287 KJ/KgK, Cv=0.713 KJ/KgK.
Take R=0.287 KJ/KgK, Cv=0.713 KJ/KgK.
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5 (a)
Explain Maxwell relations.
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5 (b)
Explain Clausius-Clapyeron Equation.
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5 (c)
An engine working on the Otto Cycle is supplied with air at 0.1 MPa and 35°C. The compression ratio is 8. Heat supplied is 2100 KJ/kg. Calculate the maximum pressure and temperature of the cycle, the cycle efficiency and mean effective pressure.
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6 (a)
Explain
i) Combustion
ii) Enthalpy of Formation
iii) Enthalpy of Combustion
iv) Adiabatic flame temperature
i) Combustion
ii) Enthalpy of Formation
iii) Enthalpy of Combustion
iv) Adiabatic flame temperature
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6 (b)
A reversible engine receives heat from two thermal reservoir maintained at constant temperature of 750K and 500K. The engine develops 100KW and rejects 3600 KJ/min of heat to a heat sink at 250K. Determine the heat supplied by each thermal reservoir and thermal efficiency of the engine.
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