Compressors

161. The work ratio of a gas turbine plant is defined as the ratio of

1. net work output and heat supplied
2. net work output and work done by turbine
3. actual heat drop and isentropic heat drop
4. net work output and isentropic heat drop
5. isentropic increase/drop in tempera¬ture and actual increase/ drop in temperature.

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162. The work ratio of simple gas turbine cycle depends on

1. pressure ratio
2. maximum cycle temperature
3. minimum cycle temperature
4. all of the above
5. none of die above.

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163. The working fluid in ai turbine is

1. in two phases
2. in three phases
3. in a single phase
4. in the form of air and water mixture
5. gas and no air.

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164. There is a certain pressure ratio (optimum) for a gas turbine at which its thermal efficiency is maximum. With increase in turbine temperature, the value of pressure ratio for the peak efficiency would

1. remain same
2. decrease
3. increase
4. unpredictable
5. none of the above.

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165. Thrust of a jet propulsion power unit can be increased by

1. burning fuel after gas turbine
2. injecting water in the compressor
3. injecting ammonia into the combustion chamber
4. all of the three above
5. none of the above.

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166. To aviod moisture troubles, the compressed air main line should

1. rise gradually towards the point of use
2. drop gradually towards the point of use
3. be laid vertically
4. be laid exactly horizontally
5. none of the above

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167. To avoid moisture troubles, the branch connections from compressed air lines should be taken from

1. top side of main
2. bottom side of main
3. left side of main
4. right side of main
5. any location.

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168. Turbo propeller has the^following additional feature over the turbojet

1. peopeller
2. diffuser
3. intercooler
4. turbine and combustion chamber
5. starting engine.

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169. Turbofan engine employs

1. one air stream
2. two or more air streams
3. no air stream
4. solid fuel firing
5. rocket principle for its operation.

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170. Volumetric efficiency is

1. the ratio of stroke volume to clearance volume
2. the ratio of the air actually delivered to the amount of piston displacement
3. reciprocal of compression ratio
4. index of compressor performance
5. proportional to compression ratio.

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