Compressors

151. The thermal efficiency of a gas turbine as compared to a diesel plant is

1. same
2. more
3. less
4. depends on other factors
5. unpredictably.

View answer

152. The thermal efficiency of a simple gas turbine for a given turbine inlet temperature with increase in pressure ratio

1. increases
2. decreases
3. first increases and then decreases
4. first decreases and then increases
5. remains same.

View answer

153. The thermodynamic efficiency of rotary compressor is based on

1. isothermal compression
2. adiabatic compression
3. isentropic compression
4. polytropic compression
5. none of the above.

View answer

154. The thrust on the rotor in a centrifugal compressor is produced by

1. radial component
2. axial component
3. tangential component
4. resultant component
5. none of the above.

View answer

155. The vloumetric efficiency of compressor with increase in compression ratio will

1. increase
2. decrease
3. remain same
4. may increase/decrease depending on clearance volume
5. none of the above.

View answer

156. The volumetirc efficiency of a compressor is calculated on the basis of

1. volume of air inhaled at working conditions
2. volume of air inhaled at N.T.P. conditions
3. volume at 0°C and 1 kg/cm2
4. volume at 20°C and 1 kg/cm2
5. none of the above.

View answer

157. The volumetric efficiency of a compressor falls roughly as follows for every 100 m increase in elevation

1. 0.1%
2. 0.5%
3. 1.0%
4. 5%
5. 10%.

View answer

158. The volumetric efficiency of a compressor falls roughly as follows for every 5°C increase in atmospheric temperature

1. 0.1%
2. 0.5%
3. 1%
4. 5%
5. 10%.

View answer

159. The weight per horse power ratio for gas. turbine as compared to I.C. engine and steam turbine is

1. same
2. higher
3. lower
4. uncomparable
5. unpredictable.

View answer

160. The work done per unit mass of air in compression will’be least when n is equal to

1. 1
2. 1.2,
3. 1.3
4. 1.4
5. 1.5

View answer