In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes_______________?

Related Mcqs:

1. The blades of a centrifugal impeller are said to be curved forward, if the ____________ of the motion of impeller blades?

   A. Inlet tip of a blade curves in a direction opposite to that
   B. Outlet tip of a blade curves in a direction opposite to that
   C. Inlet tip of a blade is towards the direction
   D. Outlet tip of a blade is towards the direction

2. Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the _______________ decreases?

   A. NPSH required
   B. BHP required by the pump
   C. Head of the liquid pumped
   D. All A., B. and C.

3. Reciprocating pumps are not able to compete with the centrifugal pump for industrial use, mainly because these pumps have_____________?

   A. Very low speeds
   B. Smaller discharge
   C. Higher capital &maintenance cost
   D. High vibrations

4. 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

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

   A. Lower than
   B. Higher than
   C. Equal to
   D. None of these

6. In case of a centrifugal pump, the ratio of total delivered pressure to pressure developed with the impeller is called the _____________ efficiency?

   A. Manometric
   B. Mechanical
   C. Volumetric
   D. Overall

7. 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

8. _____________________ pumps are a group of vacuum pumps ?

   A. Hyster
   B. Sump
   C. Mono
   D. Submerged

9. ______________ pumps are axial flow pumps?

   A. Turbine
   B. Propeller
   C. Diffuser
   D. None of these

10. What causes cavitation in centrifugal pump ?

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