# Turbo Machines Test Questions Set - 2

1)   Which component of fluid velocity is responsible for transmission of power through rotodynamic machine?

b. Axial
c. Tangential
d. None of the above
 Answer  Explanation  Related Ques ANSWER: Tangential Explanation: No explanation is available for this question!

2)   What is the general energy equation for transfer of energy between the fluid and machine?

Where,
Vw1 = Tangential component of the velocity of fluid at the entry of the rotor
Vw2 = Tangential component of the velocity of fluid at the exit of the rotor
u1 = Peripheral velocity of fluid at the entry of the rotor
u2 = Peripheral velocity of fluid at the exit of the rotor
ṁ = Flow rate of fluid

a. E = ṁ (Vw1 – Vw2) x (u1 – u2)
b. E = ṁ (Vw1 – Vw2) / (u1 – u2)
c. E = ṁ (Vw1 u1 – Vw2 u2)
d. E = ṁ (Vw1 u1 – Vw2 u2)2
 Answer  Explanation  Related Ques ANSWER: E = ṁ (Vw1 u1 – Vw2 u2) Explanation: No explanation is available for this question!

3)   If (Vw1 u1 – Vw2 u2), then machine is called as________.

a. compressor
b. turbine
c. pump
d. all of the above
 Answer  Explanation  Related Ques ANSWER: turbine Explanation: No explanation is available for this question!

4)   Consider the below diagram of jet of water striking flat stationary plate normal to jet. What will be the phase of workdone on the plate? a. negative
b. positive
c. zero
d. unpredictable
 Answer  Explanation  Related Ques ANSWER: zero Explanation: No explanation is available for this question!

5)   Consider the following diagram of jet of water striking flat stationary plate inclined at an angle θ. What will be the phase of workdone on the plate? a. negative
b. positive
c. zero
d. unpredictable
 Answer  Explanation  Related Ques ANSWER: zero Explanation: No explanation is available for this question!

6)   What is the head of water available at turbine inlet in hydro-electric power plant called?

b. tail race

7)   Gross head is the difference between __________.

a. head race and tail race
c. head race and friction losses
d. net head and friction losses
 Answer  Explanation  Related Ques ANSWER: head race and tail race Explanation: No explanation is available for this question!

8)   Which of the following hydraulic turbines has a construction given in diagram below? a. Kaplan turbine
b. Francis turbine
c. Pelton turbine
d. Propeller turbine
 Answer  Explanation  Related Ques ANSWER: Pelton turbine Explanation: No explanation is available for this question!

9)   What is runaway speed of the runner of Pelton wheel?

a. maximum unsafe speed of the runner due to sudden increase in load on turbine
b. minimum safe speed of the runner due to sudden increase in load on turbine
c. maximum unsafe speed of the runner due to sudden decrease in load on turbine
d. minimum safe speed of the runner due to sudden decrease in load on turbine
 Answer  Explanation  Related Ques ANSWER: maximum unsafe speed of the runner due to sudden decrease in load on turbine Explanation: No explanation is available for this question!

10)   What is the formula for the velocity of water jet at the inlet of turbine?

Where,
H = Net head acting on Pelton wheel
Cv = coefficient of velocity of jet

a. V = CvgH
b. V = 2 CvgH
c. V = Cv2gH
d. V = 2 Cv g √H
 Answer  Explanation  Related Ques ANSWER: V = Cv √2gH Explanation: No explanation is available for this question!

11)   The gates of aerofoil section in between the outer and inner ring of guide wheel are called as ________.

a. guide gates
b. guide vanes
c. scrolling gates
d. scrolling vanes
 Answer  Explanation  Related Ques ANSWER: guide vanes Explanation: No explanation is available for this question!

12)   Which of the following components of reaction turbine increases the head on the turbine by an amount equal to the height of runner outlet above the tail race?

a. Scroll casing
b. Guide vanes
c. Moving vanes
d. Draft tube
 Answer  Explanation  Related Ques ANSWER: Draft tube Explanation: No explanation is available for this question!

13)   As the reaction turbine works on the principle of impulse and reaction, it follows the law of ________.

a. impulse momentum
b. angular momentum
c. both a. and b.
d. none of the above
 Answer  Explanation  Related Ques ANSWER: angular momentum Explanation: No explanation is available for this question!

14)   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  Explanation  Related Ques ANSWER: Reaction turbine Explanation: No explanation is available for this question!

15)   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  Explanation  Related Ques ANSWER: mostly due to change in pressure head and small amount of work is due to change in kinetic energy Explanation: No explanation is available for this question!

16)   Consider the following (h-S) diagram of steam passing through a nozzle. Which is the correct path followed by steam when total friction loss occurs in divergent section.

Where,
p1 = pressure at the inlet of nozzle
p2 = pressure at the exit of nozzle
pt = pressure at the throat of nozzle a. 1 – 2 – 3
b. 1 – 2 – 3'
c. 1 – 2 – 3''
d. None of the above
 Answer  Explanation  Related Ques ANSWER: 1 – 2 – 3'' Explanation: No explanation is available for this question!

17)   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  Explanation  Related Ques ANSWER: Cc = √(ηn) Explanation: No explanation is available for this question!

18)   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  Explanation  Related Ques ANSWER: coefficient of discharge Explanation: No explanation is available for this question!

19)   Which of the following sentences are correct for steam turbine?

1. Steam turbine requires large floor area
2. Steam turbine is a rotary high speed machine
3. Steam turbine has low weight to power ratio
4. Steam turbine has more initial cost and maintenance cost

a. (1) and (2)
b. (2) and (3)
c. (3) and (4)
d. (1) and (4)
 Answer  Explanation  Related Ques ANSWER: (2) and (3) Explanation: No explanation is available for this question!

20)   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  Explanation  Related Ques ANSWER: (Blade velocity) / (Steam velocity at inlet) Explanation: No explanation is available for this question!

21)   Discharge capacity of the reciprocating pump is __________ that of the centrifugal pump.

a. higher than
b. lower than
c. same as
d. unpredictable
 Answer  Explanation  Related Ques ANSWER: lower than Explanation: No explanation is available for this question!

22)   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  Explanation  Related Ques ANSWER: Reciprocating pump Explanation: No explanation is available for this question!

23)   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  Explanation  Related Ques ANSWER: priming Explanation: No explanation is available for this question!

24)   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  Explanation  Related Ques ANSWER: single stage, horizontal Explanation: No explanation is available for this question!

25)   Which of the following centrifugal pumps has higher specific speed than the others?

a. Axial flow
c. Mixed flow
d. All have same specific speed
 Answer  Explanation  Related Ques ANSWER: Axial flow Explanation: No explanation is available for this question!

26)   Angular momentum of gas in the free vortex of vaneless diffuser ___________.

a. increases
b. decreases
c. remains constant
d. becomes unpredictable
 Answer  Explanation  Related Ques ANSWER: remains constant Explanation: No explanation is available for this question!

27)   Vaneless diffusers are suitable for ___________.

a. only low pressure rise
b. only high pressure rise
c. both low as well as high pressure rise

 Answer  Explanation  Related Ques ANSWER: only low pressure rise Explanation: No explanation is available for this question!

28)   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  Explanation  Related Ques ANSWER: 1/3 rd of Explanation: No explanation is available for this question!

29)   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  Explanation  Related Ques ANSWER: slip factor Explanation: No explanation is available for this question!

30)   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  Explanation  Related Ques ANSWER: Pressure coefficient Explanation: No explanation is available for this question!

31)   ___________ 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  Explanation  Related Ques ANSWER: Degree of reaction Explanation: No explanation is available for this question!

32)   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  Explanation  Related Ques ANSWER: Both a. and b. Explanation: No explanation is available for this question!

33)   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  Explanation  Related Ques ANSWER: Mean work input factor (Ψw) decreases Explanation: No explanation is available for this question!

Where,
W = Workdone
Cf = Axial flow velocity

a. Ψ = W / (Cf)2
b. Ψ = (Cf)2 / W
c. Ψ = W / (Cb)2
d. Ψ = (Cb)2 / W
 Answer  Explanation  Related Ques ANSWER: Ψ = W / (Cb)2 Explanation: No explanation is available for this question!

35)   What is the effect of increasing flow coefficient (Φ) in an axial flow compressor on blade loading coefficient (Ψ)?