Solve any one question from Q1 and Q2

1 (a)
Explain the following concepts of thermodynamics:

i) Thermodynamics cycle

ii) Flow work

iii) P-dV work.

i) Thermodynamics cycle

ii) Flow work

iii) P-dV work.

6 M

1 (b)
Find the change in entropy of universe when 1 kg of ice at -5°C is exposed to atmosphere which is at 30°C, ice melts and comes in thermal equilibrium with atmosphere. Consider specific heat of ice 2.1 kJ/kgK, latent heat of fusion of ice 330 kJ/kg.

6 M

2 (a)
What are the Kelvin-Planck and Clausius statements of second law of thermodynamic? Also establish their equivalence.

6 M

2 (b)
Air is initially at 1 bar and 27°C is compressed reversibly and adiabatically in reciprocating engine to final pressure of 25 bar. Find work done, change in enthalpy and change in entropy per kg of air. Assume C

_{p}and C_{v}of air 1.005 kJ/kg K and 0.717 kJ/kgK respectively.
6 M

Solve any one question from Q3 and Q4

3 (a)
Draw P-V and T-S diagram of Otto cycle and derive an expression to find its thermal efficiency.

6 M

3 (b)
A sample of steam generated in a boiler at a pressure of 12 bar is passed through separating and throttling calorimeter to measure its dryness fraction. The following observations were recorded during the test:

i) Pressure of steam after throttling - 1.2 bar,

ii) Temperature of steam after throttling - 120°C

iii) Mass of steam collected after throttling -1 kg

iv) Mass of water collected through separating calorimeter -15gm.

Find the quality of steam generated by boiler. Assume C

i) Pressure of steam after throttling - 1.2 bar,

ii) Temperature of steam after throttling - 120°C

iii) Mass of steam collected after throttling -1 kg

iv) Mass of water collected through separating calorimeter -15gm.

Find the quality of steam generated by boiler. Assume C

_{P}of superheated steam 2.1 kJ/kgK.
6 M

4 (a)
Prove that when heat is transfer through finite temperature difference it causes loss of available energy.

6 M

4 (b)
A thermal power plant works on Rankine Cycle has a boiler pressure of 120 bar and condenser pressure of 5 kPa. Steam is superheated in the superheater to 400°C. Find per kg of steam generated by boiler:

i) Net work output

ii) Rankine efficiency

iii) Specific team consumption.

i) Net work output

ii) Rankine efficiency

iii) Specific team consumption.

6 M

Solve any one question from Q5 and Q6

5 (a)
With the help of suitable diagram explain the construction and working of Cochron boiler.

6 M

5 (b)
Determine the air-fuel ratio for an oil fired steam generator with the following data:

Chimney height - 32 m,

Chimney draught - 12 mm of water column,

Flue gas temperature through chimney - 279°C

Ambient air temperature - 27°C

Also calculate the velocity of flue gas through chimney neglecting losses in the flow of flue gas through chimney.

Chimney height - 32 m,

Chimney draught - 12 mm of water column,

Flue gas temperature through chimney - 279°C

Ambient air temperature - 27°C

Also calculate the velocity of flue gas through chimney neglecting losses in the flow of flue gas through chimney.

7 M

6 (a)
Write the function and locations of the following boiler mountings:

i) Blow off cock

ii) Fusible plug

iii) Steam safety value.

i) Blow off cock

ii) Fusible plug

iii) Steam safety value.

6 M

6 (b)
The following readings were recorded during boiler trail of 6 hour duration:

Pressure of steam generated - 12 bar,

Mass of steam generated - 4000 kg

Dryness fraction of steam generated - 0.85

Feed water temperature - 30°C,

Coal used - 4000 kg.

Calorific value of coal - 33400 kJ/kg.

Find:

i) Factor of equivalent evaporation

ii) Equivalent evaporation from and at 100°C

iii) Efficiency of boiler.

Pressure of steam generated - 12 bar,

Mass of steam generated - 4000 kg

Dryness fraction of steam generated - 0.85

Feed water temperature - 30°C,

Coal used - 4000 kg.

Calorific value of coal - 33400 kJ/kg.

Find:

i) Factor of equivalent evaporation

ii) Equivalent evaporation from and at 100°C

iii) Efficiency of boiler.

7 M

Solve any one question from Q7 and Q8

7 (a)
Write the complete combustion equations for C

_{8}H_{18}and C_{12}H_{26}. Also find theoretical air required for complete combustion of 1 kg of these fuels.
6 M

7 (b)
If 30% excess air is supplied for the combustion of dry anthracite of the following compositions by mass: Carbon - 88%, Hydrogen - 4%, Oxygen - 3.5%, Sulphur - 0.5%, Ash - 3% and Nitrogen - 1%, determine:

i) Air-fuel ratio

ii) Dry analysis of product of combustion by volume.

i) Air-fuel ratio

ii) Dry analysis of product of combustion by volume.

7 M

8 (a)
With the help of suitable diagram explain, how Junker gas calorimeter is used to measure Calorific value of gases fuel?

6 M

8 (b)
Diesel fuel (C

_{12}H_{26}) reacts with 80% theoretical air. Determine the product of combustion on percentage of volume basis. Considering complete combustion of hydrogen of fuel.
7 M

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