Download AKTU B-Tech 4th Sem 2015-16 401EME Applied Thermodynamics Question Paper

Printed Pages: 6

NME-401/EMEA401

(Following Paper ID and Roll No. to be filled in your Answer Books)

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Paper ID: 140408

B.TECH.

Theory Examination (Semester-IV) 2015-16

APPLIED THERMODYNAMICS

Time: 3 Hours

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Max. Marks : 100

Section-A

Q1. Attempt all parts. All parts carry equal marks. Write answer of each part in short. (2×10=20)

1. Define the heat rate using in the Rankine cycle.
2. Define propulsive power and propulsive efficiency.
3. Explain about congeneration.

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4. Explain the significance of Willian's law in steam engines.
5. How Equivalent evaporation is used for comparison of boilers?

Section-B

Attempt any five question. Each question carries equal marks. (5×10=50)

1. What do you understand by inversion curve? Define Joules coefficient. How these can be used for refrigeration?
2. A sample fuel has the following percentage composition by weight, Carbon = 84% hydrogen = 10%, oxygen = 3.5% nitrogen = 1.5% and Ash = 1%.
   1. Determine the stoichiometric air fuel ratio by mass.

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   2. If 20% excess air is supplied, find percentage composition of dry fuel gas by volume.
3. A double acting single cylinder steam engine runs at 250 rpm and develops 30 kW. The pressure limits of operation are 10 bar and 1 bar. Cut off is 40% of the stroke. The L/D ratio is 1.25 and diagram factor is 0.75. Assume dry saturated steam at inlet, hyperbolic expansion and negligible effect of piston rod. Find:
   1. Mean effective pressure
   2. Cylinder dimensions
   3. Indicated thermal efficiency of the cycle.

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4. An impulse steam turbine of 180 kW has steam flowing at rate of 165 kg/min and leaving axially. Steam turbine blade speed is 175 m/s and it leaves nozzle at 400 m/s. For the blade velocity coefficient of 0.9. diagrams explain the difference between the working of a propeller turbine and a jet turbine.
5. Explain about Reheat stae turbine. If the maximum temperature (Tmax K) and minmum temperature (Tmin, K) in the cycle remain constant, show that for maximum specific output of the plant, the optimum overall pressure ratio is given by

Section-C

Attempt any two question. Each question carries equal marks. (2×15=30)

1. Q3. The following data refer to a single stage impulse turbine: Isentropic nozzle heat drop = 251 kJ/kg: nozzle efficiency = 90% : nozzle angle = 20° : ratio of blade speed to whirl component of steam speed = 0.5: blade velocity co-efficient = 0.9; the velocity of steam entering the nozzle = 20m/s. Determine:
   1. The blade angles at inlet and outlet if the steam enters in to the blades without shock and leaves the blades in an axial direction.

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   2. pt = (?t. ?c. Tmax/Tmin) 27/3(?-1) Where ? - Adiabatic index : ?1= Isentropic efficiency of the turbine. ? = Isentropic efficiency of compressor.
2. Q5. A boiler generate 7.5 kg of steam per kg of coal burnt at a pressure of 11 bar, from feed water having a temperature of 70°C. The efficiency of boiler is 75% and factor of evaporation 1.15. specific heat of steam at constant pressure is 2.3. Calculate:
   1. Degree of superheat if the temperature of steam generated;
   2. Calorific value of coal in kJ/kg;
   3. Equivalent evaporation in kg of steam per kg of coal.

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