In centrifugal pump operation, the cavitation can be eliminated by maintaining suction pressure ______________ the vapor pressure of the liquid at the suction temperature?

Related Mcqs:

1. Cavitation occurs in a centrifugal pump when the suction pressure is________________?

   A. Less than the vapour pressure of the liquid at that temperature
   B. Greater than the vapour pressure of the liquid at that temperature
   C. Equal to the vapour pressure
   D. Equal to the developed head

2. Cavitation in a pump creates so many undesirable effects. Out of the following, which is not an undesirable effect created by cavitation ?

   A. Decrease in effect
   B. Increase in thrust
   C. Develops noise
   D. Develops high pressure

3. The excess of the sum of pressure & velocity heads over the vapor pressure of the liquid at the suction is called the___________________?

   A. Static submergence
   B. Net positive suction head (NPSH)
   C. Cavitation sensitivity
   D. Priming

4. The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the_________________?

   A. Discharge
   B. Suction
   C. Suction minus vapor pressure of the liquid at suction temperature
   D. Discharge minus vapor pressure of the liquid at the discharge temperature

5. A centrifugal pump is used to pump water through a horizontal distance of 150 m, and then raised to an overhead tank 10 m above. The pipe is smooth with an I.D of 50 mm. What head (m of water) must the pump generate at its exit E. to deliver water at a flow rate of 0.001 m3/s? The Fanning friction factor, f is 0.0062 ?

   A. 10 m
   B. 11 m
   C. 11.8 m
   D. 30 m

6. A centrifugal pump used to pump water is used to pump an oil with specific gravity of 0.8 at the same rate. The power consumption will now_________________?

   A. Increase
   B. Decrease
   C. Remain same
   D. Data insufficient to predict

7. A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump_________________?

   A. Develops a lower head
   B. Capacity is reduced
   C. Requires more power
   D. All A., B. and C.

8. Cavitation in a centrifugal pump can be avoided by keeping the__________________?

   A. Inlet pressure high
   B. Outlet pressure low
   C. Inlet pressure low
   D. Outlet pressure high

9. What causes cavitation in centrifugal pump ?

   A. High suction pressure
   B. Low barometric pressure
   C. Low suction pressure
   D. High suction velocity

10. Foot valves are provided in the suction line of a centrifugal pump to ____________________?

    A. Avoid priming, every time we start the pump
    B. Remove the contaminant present in the liquid
    C. Minimise the fluctuation in discharge
    D. Control the liquid discharge