Hydrolic Mechines online Quiz Questions

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1. Reciprocating pumps are no more to be seen in industrial applications (in comparison to centrifugal pumps) because of _____.
high initial and maintenance cost	lower discharge
lower speed of operation	necessity of air vessel

2. In a centrifugal pump casing, the flow of water leaving the impeller, is _____.
rectilinear flow	radial flow
free vortex motion	forced vortex

3. Head developed by a centrifugal pump depends on _____.
impeller diameter	speed
fluid density	(a) and (b) above

4. For starting an axial flow pump, its delivery valve should be _____.
closed	open
depends on starting condition and flow desired	could be either open or closed

5. The efficiency of a centrifugal pump is maximum when its blades are ______.
straight	bent forward
bent backward	bent forward first and then backward

6. In a centrifugal pump casing, the flow of water leaving the _____.
radial	centrifugal
rectilinear	vortex

7. Centrifugal pump is started with its delivery valve
kept fully closed	kept fully open
irrespective of any position	kept 50% open

8. Axial flow pump is started with its delivery valve ______.
kept fully closed	kept fully open
irrespective of any position	kept 50% open

9. When a piping system is made up primarily of vertical lift and very little pipe friction, the pump characteristics should be _____.
horizontal	nearly horizontal
steep	first rise and then fall

10. One horsepower is equal to _____.
102 watts	75 watts
550 watts	735 watts

11. Multistage centrifugal pumps are used to obtain
high discharge	high head
pumping of viscous fluids	high head and high discharge

12. When a piping system is made up primarily of friction head and very little of vertical lift, then pump characteristics should be ____.
horizontal	nearly horizontal
steep	first rise and then fall

13. In a single casing, multi-stage pump running at constant speed, the capacity rating is to be slightly lowered. It can be done by ____.
designing new impeller	trimming the impeller size to the required size by machining
not possible	some other alterations in the impeller

14. If a pump is handling water and is discharging a certain flow Q at a constant total dynamic head requiring a definite B.H.P., the same pump when handling a liquid of specific gravity 0.75 and viscosity nearly same as of water would discharge
same quantity of liquid	0.75 Q
Q/0.75	1.5 Q

15. The horse power required in above case will be _____.
same	0.75 B.H.P.
B.H.P./0.75	1.5 B.H.P

16. Low specific speed of a pump implies it is _____.
centrifugal pump	mixed flow pump
axial flow pump	any one of the above

17. The optimum value of vane exit angle for a centrifugal pump impeller is ______.
10-15°	20-25°
30-40°	50-60°

18. In a centrifugal pump, the liquid enters the pump _____.
at the top	at the bottom
at the centre	from sides

19. For small discharge at high pressure, following pump is preferred _____.
centrifugal	axial flow
mixed flow	reciprocating

20. In centrifugal pumps, maximum efficiency is obtained when the blades are _____.
straight	bent forward
bent backward	radial

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