APPLIED THERMODYNAMICS PAPER

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APPLIED THERMODYNAMICS 3rd Semester (ME 207/209) Dec 2006

I

1. What is triple point?
2. Write a note on Molllier chart.
3. Two advantages of reheat cycle.
4. Highlight the use of economizer.
5. Shoe the effect of friction in diffuser section in convergent and divergent nozzle on H-S diagram.
6. What is stage efficiency?
7. What is the condition of steam leaving from the turbine without shock?
8. Why compounding of turbines is essential?
9. What is after-cooling in air compressor?
10. What is Dalton’s law of partial pressure?

II) What is the criterion of selecting a boiler? Distinguish between fir tube and water tube boiler.
III) With the help of a neat sketch, explain the working of sterling boiler and its essential features.
IV) A convergent divergent nozzle is required to discharge 2 kg of steam/sec. The nozzle is supplied with steam at 7 bar 180 oC and discharge takes place against a back pressure of 1 bar. Expansion up to throat is isentropic and frictional resistance between throat and exit is equivalent to 62 kJ/kg. Taking approach velocity 75 m/z and throat pressure is 4 bar, estimate suitable areas of throat and exit.
V) Steam with absolute velocity of 300 m/s is supplied through a nozzle to a single stage impulse turbine. The nozzle angle is 25 o. The dia of rotor is 1 m and has speed of r.p.m. Find blade angles for zero axial thrust. If the blade velocity coefficient is 0.9 and steam flow rate is 10 kg/s, Calculate power.
VI) Explain with a neat sketch a regenerative cycle with two bleeding points. Derive the expression for its thermal efficiency.
VII) A 3 stage compressor is used to compress air from 1.0 bar to 36 bar. The compression is as per the law pv1.25. The temperature of air at inlet of compressor is 300 K. Neglecting the clearance and assuming perfect inter cooling, find out the indicated power in kW to deliver 15 m3/ min air measured at inlet conditions and find intermediate pressures also.
VIII) A surface condenser is designed to handle 9000 kg of steam per hour. The steam enters at 0.06 bar absolute and dryness fraction is 0.88. The condensate leaves at the corresponding saturation temperature. The pressure is constant throughout the condenser. Estimate the cooling water flow rate/hr if the cooling water temperature rise is limited to 10 oC.
IX )(a) What do you understand by supersaturated flow in a nozzle?
(b) What are the limitations of chimney draught?