APPLIED THERMODYNAMICS & THERMAL ENGIN..PREVIOUS Q.PAPERS
II B.TECH - II SEMESTER EXAMINATIONS, APRIL/MAY, 2011
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APPLIED THERMODYNAMICS – I
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Time: 3hours
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(MECHANICAL ENGINEERING)
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Max. Marks: 75
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Answer any FIVE questions
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All Questions Carry Equal Marks
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1.a) Derive the equation for efficiency of diesel cycle.
b) A four stroke diesel engine has a bore of 25 cm and stroke of 40 cm. Cut off takes place at 8% of the stroke and initial pressure of the cycle is 0.1 MPa. Calculate the air
standard efficiency, m.e.p. and power developed by the engine if it is running at
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400 rpm.
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[7+8]
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2.a)
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With the help of a line diagram, explain the fuel atomizer.
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b)
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Differentiate between indicator diagram and valve timing diagram.
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[7+8]
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3. With all minute details, explain the factors affecting the knocking including the fuel
characteristics for S I Engines and C I Engines.
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[15]
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4.a)
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With the help of diagrams, explain different combustion chambers used in CI engines
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and advantages of each.
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b)
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What is meant by delay period and explain factors affecting the delay period.
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[8+7]
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5.a) Derive an equation for the work done in single stage reciprocating compressor neglecting the clearance volume.
b) Air at 1 bar and 270C is taken into single stage single acting reciprocating air compressor with law of pv1.1 = constant to a final pressure of 7 bar and compressor takes 1 m3/min. Calculate the indicated power and isothermal efficiency. Also calculate the cylinder dimensions and power of the motor required to drive compressor. Speed of compressor is 5 rps. Stroke to bore ratio 1.5:1, ηmech = 85%,
ηtransmission = 90%.[7+8]
6. A 4 cylinder 4 – stroke petrol engine having bore 6 cm and stroke 10 cm develops 65 N-m torque at 3000 RPM. Find the fuel consumption of the engine in kg/hr and brake mean effective pressure, if the relative efficiency of 50% and clearance volume
is 60 cm3. Take CV = 40 MJ/kg.
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[15]
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7.a) Explain the working details of steady flow rotary compressors and p – v curves of the same.
b) Derive the equation for the thermodynamics cycle work done for a rotary compressor.
[8+7]
8.
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Write short notes:
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a) Fuel rating methods.
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b) p-θ diagrams in Engine testing.
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c) Velocity triangles for axial flow compressor.
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[15]
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