Pump Theory Flashcards
1
Q
What is the equation for the theoretical power of a PD pump?
A
2
Q
Can PD pumps be given a coefficient of discharge (Cd)?
A
Yes
3
Q
What is slip?
A
- Slip is the % difference between the theoretical and actual flow.
- Higher the slip, the less efficient the pump.
- Result of, usually, fluid passing back through the valves on the pump to the suction side.
- Could also be losses through fittings and pipes.
4
Q
What is the calulation for Slip %?
A
5
Q
What is the calulation for Euler head?
A
6
Q
How do you calulate the efficiency of a centrifugal pump?
A
The manometric head dicided by the Euler head.
(Equation in equation Book)
7
Q
What happens when two pumps are in series?
A
Never place PD pumps in series.
8
Q
What happens when you place pumps in parallel?
A
9
Q
What happens to a centrifugal pump when density of a fluid changes?
A
- Small changes in density have little effect on pump rating or efficiency.
- Power requirement increases the denser the fluid.
10
Q
When can vapour lock occur in a centrifugal pump?
A
Volatile fuels can cause vapour lock as they vaporise more easily in lower pressures.
11
Q
What happens when viscosity of a fluid increases in a centrifugal pump?
A
- Efficiency decreases - opposed to a PD pump where it increases.
- H/Q curve drops significantly as flow increases.
