Compressors, Gas Turbines and Jet Engines Objective Questions with Answers - Set 13 - ObjectiveBooks
Compressors, Gas Turbines and Jet Engines Objective Questions with Answers - Set 13

Compressors, Gas Turbines and Jet Engines Objective Questions with Answers - Set 13

Practice Test: Question Set - 13

1. A jet engine has
    (A) No propeller
    (B) Propeller in front
    (C) Propeller at back
    (D) Propeller on the top
2. The material commonly used for air craft gas turbine is
    (A) Stainless steel
    (B) High alloy steel
    (C) Duralumin
    (D) Timken, Haste alloys
3. In open cycle turbojet engines used in military aircraft, reheating the exhaust gas from the turbine by burning, more fuel is used to increase the
    (A) Thrust and range of aircraft
    (B) Efficiency of the engine
    (C) Both (A) and (B)
    (D) None of these
4. It is not possible to use closed gas turbine cycle in aeronautical engines because
    (A) It is inefficient
    (B) It is bulky
    (C) It requires cooling water for its operation
    (D) None of the above
5. The combustion efficiency of a gas turbine using perfect combustion chamber is of the order of
    (A) 75%
    (B) 85%
    (C) 90%
    (D) 99%
6. For an irreversible gas turbine cycle, the efficiency and work ratio both depend on
    (A) Pressure ratio alone
    (B) Maximum cycle temperature alone
    (C) Minimum cycle temperature alone
    (D) Both pressure ratio and maximum cycle temperature
7. Separators are generally used in air compressor installations
    (A) Before the inter-cooler
    (B) After the inter-cooler
    (C) Between the after-cooler and receiver
    (D) Before first stage suction
8. Producer gas is produced by
    (A) Carbonisation of coal
    (B) Passing steam over incandescent coke
    (C) Passing air and a large amount of steam over waste coal at about 65°C
    (D) Partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast
9. Water gas is produced by
    (A) Carbonisation of coal
    (B) Passing steam over incandescent coke
    (C) Passing air and a large amount of steam over waste coal at about 65°C
    (D) Partial combustion of coal, eke, anthracite coal or charcoal in a mixed air steam blast
10. In a single stage, single acting reciprocating air compressor without clearance volume, the work-done is maximum during
    (A) Isothermal compression
    (B) Isentropic compression
    (C) Polytropic compression
    (D) None of these
11. Water is injected in gas turbine cycle to
    (A) Control temperature
    (B) Control output of turbine
    (C) Control fire hazards
    (D) Increase efficiency
12. A gas turbine used in air craft should have
    (A) High h.p. and low weight
    (B) Low weight and small frontal area
    (C) Small frontal area and high h.p.
    (D) High speed and high h.p.
13. The volumetric efficiency for reciprocating air compressors is about
    (A) 10 to 40%
    (B) 40 to 60%
    (C) 60 to 70%
    (D) 70 to 90%
14. In the axial flow gas turbine, the work ratio is the ratio of
    (A) Compressor work and turbine work
    (B) Output and input
    (C) Actual total head temperature drop to the isentropic total head drop from total head inlet to static head outlet
    (D) Actual compressor work and theoretical compressor work
15. The degree of reaction of an axial flow turbine is the ratio of isentropic temperature drop in a blade row to the
    (A) Adiabatic temperature drop in the stage
    (B) Total temperature drop
    (C) Total temperature drop in the stage
    (D) Total adiabatic temperature drop
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