Top 80+ Solved Turbo Machines MCQ Questions Answer
Q. As a result of blade friction, the outlet relative velocity of impulse turbine compared to inlet relative velocity is
a. Nearly same
b. 2% less
c. 10% - 15% less
d. 30% less
Q. As there is plenty of time for heat transfer across the walls, the flow in long pipes at low velocities attains
a. adiabatic conditions
b. isothermal conditions
c. polytropic conditions
d. isentropic conditions
Q. The normal shock wave in compressible flow is analogous to
a. hydraulic bore in tidal rivers
b. vortex formation in centrifugal pump
c. hydraulic jump in channel flow
d. surges in open channel
Q. Greater the difference between jet velocity and aeroplane velocity
a. greater the propulsive efficiency
b. Lesser the propulsive efficiency
c. unaffected is the propulsive efficiency
d. None of the above
Q. If stage efficiency is S, blade efficiency is B and nozzle efficiency in N, then
a. BSN = 1
b. N = S
c. S = B.N
d. B = SN
Q. Choking is
a. Variation of mass flow rate in proportion to pressure ratio
b. variation of mass flow rate in inverse proportion to pressure ratio
c. fixed mass flow rate regardless of pressure ratio
d. none of the above
Q. The advantage of closed cycle gas turbine over open cycle gas turbine is
a. no contamination of working substance with combustion gases
b. inferior quality fuel can be used
c. low maintenance costs
d. All of the above
Q. Brayton cycle cannot be used in reciprocating engines even for same compression ratio and work output because
a. Large volume of low pressure gas cannot be efficiently handled in reciprocating engines
b. Brayton cycle is less efficient
c. Otto cycle is more efficient
d. Brayton cycle is for slow speed engines only
Q. Working medium for closed cycle gas turbine should have
a. high molecular weight
b. low specific volume
c. higher adiabatic index
d. lower specific speed
Q. Thermal efficiency of a gas turbine cycle can be improved by
a. reheating between expansion stage
b. intercooling between compression stges
c. regeneration
d. any of the above
Q. Thermal efficiency of closed cycle gas turbine plant increases by
a. reheating
b. intercooling
c. regenerator
d. All of the above
Q. For gas turbine, compressors used are
a. Centrifugal type
b. Lobe type
c. Axial flow type
d. Reciprocating type
Q. Which of the following is the least efficient method of governing steam turbines?
a. Combined throttle and nozzle governing
b. Throttle governing
c. Nozzle control governing
d. Bypass governing
Q. The effect of blade friction in a steam turbine is to
a. increase the specific output
b. reduce work done
c. reheat the steam
d. reduce exhaust pressure
Q. In rotory compressors, the ratio of isentropic work to Eulers work is known as
a. degree of reaction
b. slip factor
c. work factor
d. pressure coefficient