Following are some of the multiple choice questions on the Gas Turbines with answers that will help the students in developing their knowledge.
Gas Turbines MCQ
2. An aftercooler is used to
3. The overall efficiency of the compressed air system is the
4. The air power of the compressor is also known as
5. Which of the following plants is smallest and lightest for generating a given amount of power?
6. Which of the following plants is smallest and lightest for generating a given amount of power?
7. The degree of reaction in an axial flow compressor is defined as the ratio of static enthalpy rise in the
8. In a reciprocating air compressor, the compression work per kg of air
9. An axial compressor gives optimum performance at high speeds and large volume flows.
10. The increase in pressure in a roots blower is entirely due to back flow of air.
11. If p1, is the pressure of air entering the L.P. cylinder and p2 is the pressure of air leaving the L.P. cylinder (or intercooler pressure), then the ratio of cylinder diameters for a single acting, two stage reciprocating air compressor with complete intercooling is given by (where D1 = Dia. of L.P. cylinder, and D2 = Dia. of H.P. cylinder)
12. The ratio of the volume of free air delivery per stroke to the swept volume of the piston, is known as
13. High air-fuel ratio in gas turbines
14. The maximum combustion pressure in gas turbine is __________ as compared to I.C. engine.
15. The compression ratio in a gas turbine is
16. The actual volume of air delivered by a compressor, When reduced to the normal temperature and pressure conditions is called compressor capacity.
17. When the temperature of air leaving the intercooler, in a two stage compression with intercooler, is __________ the original atmospheric air temperature, then the intercooling is known as perfect or complete intercooling.
18. Intercooling in gas turbines
19. A closed cycle gas turbine gives __________ efficiency as compared to an open cycle gas turbine.
20. A large clearance Volume in a reciprocating compressor results in
21. In a centrifugal compressor, an increase in speed at a given pressure ratio causes
22. A rotary compressor is driven by an
23. Workdone by a two-stage reciprocating air compressor per cycle is equal to the workdone in LP. cylinder and H.P. cylinder.
24. Rotary compressors are used for delivering
25. The efficiency of a jet engine is higher at
26. The type of rotary compressor used in gas turbines, is of
27. In the aircraft propellers
28. For a two stage reciprocating compressor, compression from p1 to p3 is with perfect intercooling and no pressure losses. If compression in both the cylinders follows the same polytropic process and the atmospheric pressure is pa, then the intermediate pressure p2 is given by
29. The inlet pressure is always __________ the discharge pressure.
30. The clearance volume in the compressor is kept minimum because it effects on volumetric efficiency.
31. The ratio of workdone per cycle to the stroke volume of the compressor is known as
32. Intercooling in multi-stage compressors is done
33. The capacity of a compressor is expressed in
34. The increase in pressure in a vane blower takes place first due to compression and then due to back flow of air.
35. An open cycle gas turbine works on the same cycle as that of a closed cycle gas turbine.
36. The total heat rejected in a reciprocating air compressor is equal to the sum of the heat rejected during polytropic compression per kg of air and heat rejected in the intercooler per kg of air.
37. The rotary compressors are suitable for large discharge of air at low pressure.
38. The volumetric efficiency for reciprocating air compressors is about
39. A rocket works with maximum overall efficiency when air-craft velocity is __________ the jet velocity.
40. The compressed air may be used
41. In a four stage compressor, if the pressure at the first and third stage are 1 bar and 16 bar, then the delivery pressure at the fourth stage will be
42. The reason for volumetric efficiency of reciprocating compressor being less than 100 percent is
43. In a jet engine, the air-fuel ratio is
44. Free air is the air at
45. Standard air is the air at
46. The work-done on a compressor will be minimum if air is taken from
47. In a double acting compressor, the air is compressed
48. The maximum delivery pressure in a rotary air compressor is
49. Propulsion efficiency of the following order is obtained in practice
50. The type of rotary compressor used in aeroplanes, is of
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