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Turbomachines Quiz | Turbomachines Multiple Choice Questions and Answers

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Questions
1 What is the relation between Velocity Coefficient (Cc) and Nozzle efficiency (ηn)?
A Cc = (1/2) (ηn)
B Cc = √(ηn)
C Cc = (ηn)2
D Cc = (ηn)3

Answer: Cc = √(ηn)
2 The ratio of actual mass flow rate (ṁa) to ideal mass flow rate (ṁi) is called as________
A nozzle coefficient
B coefficient of nozzle friction
C coefficient of discharge
D coefficient of mass

Answer: coefficient of discharge
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3 The blade speed ratio of impulse turbine is given as ___________
A (Blade velocity) / (Steam velocity at inlet)
B (Blade velocity) / (Steam velocity at exit)
C (Steam velocity at inlet) / (Blade velocity)
D (Steam velocity at exit) / (Blade velocity)

Answer: (Blade velocity) / (Steam velocity at inlet)
4 Discharge capacity of the reciprocating pump is __________ that of the centrifugal pump.
A higher than
B lower than
C same as
D unpredictable

Answer: lower than
5 Which pump is more suitable for an application where very high pressure is required to be developed at moderate discharge?
A Reciprocating pump
B Centrifugal pump
C Turbine
D None of the above

Answer: Reciprocating pump
6 The process of filling the liquid into the suction pipe and pump casing upto the level of delivery valve is called as _________.
A filling
B pumping
C priming
D leveling

Answer: priming
7 The volute pumps and vortex volute pumps are __________ pumps with _________ shaft.
A multistage, horizontal
B multistage, vertical
C single stage, horizontal
D single stage, vertical

Answer: single stage, horizontal
8 Which of the following centrifugal pumps has higher specific speed than the others?
A Axial flow
B Radial flow
C Mixed flow
D All have same specific speed

Answer: Axial flow
9 Angular momentum of gas in the free vortex of vaneless diffuser ___________.
A increases
B decreases
C remains constant
D becomes unpredictable

Answer: remains constant
10 Vaneless diffusers are suitable for ___________.
A only low pressure rise
B only high pressure rise
C both low as well as high pressure rise
D None

Answer: only low pressure rise
11 The diffuser blades are kept ______ the number of impeller blades .
A 1/10 th of
B 1/3 rd of
C 10 times
D 3 times

Answer: 1/3 rd of
12 The ratio of actual whirl velocity to the ideal whirl velocity in the centrifugal compressor is called as _________.
A velocity factor
B slip factor
C work factor
D none of the above

Answer: slip factor
13 What is the ratio of isentropic work to Euler work in an centrifugal compressor called?
A Work coefficient
B Velocity coefficient
C Pressure coefficient
D Flow coefficient

Answer: Pressure coefficient
14 ___________ can be defined as the ratio of the pressure rise in rotor blades to the pressure rise in stages in an axial flow compressor.
A Degree of pressure
B Degree of reaction
C Pressure ratio
D Reaction ratio

Answer: Degree of reaction
15 What is the ratio of the actual work absorbed by an axial flow compressor to the theoretical work called?
A Work input factor
B Workdone factor
C Both a. and b.
D None of the above

Answer: Both a. and b.
16 What is the effect of increasing number of stages in axial flow compressor on the mean work input factor (Ψw)?
A Mean work input factor (Ψw) decreases
B Mean work input factor (Ψw) increases
C Mean work input factor (Ψw) remains constant
D Unpredictable

Answer: Mean work input factor (Ψw) decreases
17 What is the effect of increasing flow coefficient (Φ) in an axial flow compressor on blade loading coefficient (Ψ)?
A Blade loading coefficient (Ψ) increases
B Blade loading coefficient (Ψ) decreases
C Blade loading coefficient (Ψ) remains constant
D Unpredictable

Answer: Blade loading coefficient (Ψ) decreases
18 What is the formula for blade loading coefficient (Ψ) for an axial flow compressor? Where, W = Workdone Cf = Axial flow velocity Cb = Blade velocity
A Ψ = W / (Cf)2
B Ψ = (Cf)2 / W
C Ψ = W / (Cb)2
D Ψ = (Cb)2 / W

Answer: Ψ = W / (Cb)2
19 In reaction turbine work is done_______________.
A totally due to change in kinetic energy of jet
B totally due to change in pressure head
C mostly due to change in pressure head and small amount of work is due to change in kinetic energy
D mostly due to change in kinetic energy and small amount of work is due to change in pressure head

Answer: mostly due to change in pressure head and small amount of work is due to change in kinetic energy
20 In which type of turbine, the runner needs to be run full of water?
A Impulse turbine
B Reaction turbine
C Both a. and b.
D None of the above

Answer: Reaction turbine
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