A 150 mm model pump rotating at 1750 rpm has the following characteristic:
|
150 mm pump at 1750 rpm
|
|
Q (m3/s)
|
H (m)
|
ri (%)
|
|
0.00
|
31.0
|
0
|
|
0.05
|
30.0
|
54
|
|
0.08
|
28.0
|
64
|
|
0.10
|
26.0
|
68
|
|
0.13
|
22.5
|
70
|
|
0.16
|
16.5
|
67
|
A geometrically similar 200 pump having a similar efficiency curve is used to pump water through 112.5 m of 150 mm pipe, f = 0.025. The static lift is 10 m. Neglecting minor losses in the pipe calculate the flow, head and power required to drive the pump under these circumstances. The pump speed is 1450 rpm.
If it is required to adjust the flow in the pipe by regulating the pump speed, estimate the speed to reduce the flow to one-half.