The Centrifugal Pump - Quiz

Quiz Question

1. The impeller has a number of impeller blades. The number mainly depends on
desired performance
noise constraints
amount and size of solid particles in the fluid
All of the above
2. The primary task of the volute is to collect the fluid from the ring diffusor and lead it to the diffusor.
True
False
3. ______________are used for pumping contaminated water in sewage plants and industrial systems.
Water supply pumps
Industrial pumps
Wastewater pumps
Circulation pumps
4. ___________equation is valid if the following conditions are met,

  1. Stationary flow – no changes over time
  2. Incompressible flow – true for most liquids
  3. Loss-free flow – ignores friction loss
  4. Work-free flow – no supply of mechanical energy
Hamilton
Bernoulli’s
Euler
Power
5. ____________is the creation of vapor bubbles in areas where the pressure locally drops to the fluid vapor pressure.
Cavitation
Bubbling area
Evaporation
None of the above
6. If Axial thrust is the sum of forces acting on the shaft in axial direction then Radial thrust is the sum of forces acting on the shaft in radial direction.
True
False
7. A number of methods makes it possible to regulate the pump performance and thereby achieve the requested performance. The most common methods are
Bypass regulation through a bypass valve
Start/stop regulation
Regulation of speed
All of the above
8. What does EEI stands for?
Energy efficiency index
Extra efficiency index
External Energy index
None of the above
9. In the derivation of Euler’s pump equation it is assumed that the flow follows the blade. In reality this is, however, not the case because the flow angle usually is smaller than the blade angle. This condition is called __________ .
Deviation
Error angle
Slip
None of the above
10. ______________means that the fluid is rotating before it enters the impeller.
Inlet rotation
Outlet rotation
Impeller rotation
None of the above
11. Which of the following is not a type of Hydraulic loss?
Flow friction
Shaft seal
Bearing
Both b & c
12. If Reynolds number is greater than 5000 then the flow is _______________ .
Laminar flow
Reynolds flow
Transition zone
Turbulent flow
13. ____________chart which shows the friction coefficient f as function of Reynold’s number and surface roughness for laminar and turbulent flows.
Reynolds
Moody
Friction
None of the above
14. Calculate the Mean velocity in a 2 meter pipe with the diameter d=32 mm and a flow of Q=10 m3/h.
3.45 m/s
10.45 m/s
7.45 m/s
8.45 m/s
15. Recirculation zones in the hydraulic components typically occur at part load when the flow is below the design flow.
True
False
16. __________loss occurs because of smaller circulation through gaps between the rotating and fixed parts of the pump.
Friction
Leakage
Displacement
None of the above
17. What are the units of Kinematic viscosity?
m2/s
cSt
Poise
Both a and b
18. Pump performance is usually described by curves of measured head and power consumption versus measured flow
True
False
19. In systems with large variations in flow and a request for constant pressure, two or more pumps can be connected in __________ .
Parallel
Perpendicular
Diagonal
Stacks
20. What does NPSH stands for?
Net Positive Singular Head
Net Positive Suction Head
Net Positive Singular Height
None of the above