This document discusses methods for predicting pump hydraulic efficiency curves. It presents calculated efficiency curves for different specific speeds and describes alternative methods for linking efficiency to factors like rotating speed and volume flow rate. Graphs show efficiency curves and how a shift factor is used to modify the base efficiency curve based on specific speed. The curves and methods presented resemble those in Karassik's textbook on pump efficiency.

1. Pump Hydraulic
Efficiency
Prediction of efficiency curves
30th September 2009
Prepared by: Cheah CangTo

2. 2Pump hydraulic efficiency
Calculated Curves
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0.0 1000.0 2000.0 3000.0 4000.0 5000.0
Flow - cu.m/hr
Head-m/Eff-%/kW
0.0
0.5
1.0
1.5
2.0
2.5NPSHmetres
Head Eff kW Rated Point NPSH
Courtesy of Jim Bryan
Efficiency curve
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY
Volume flow rate (m3
/hr)

3. 3Pump hydraulic efficiency
Courtesy of Jim Bryan
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY
0
20
40
60
80
100
120
0 20 40 60 80 100 120 140
(Q/Q_oo) x 100
(Efficiency/Efficiency_oo)x100
Ns20
Ns40
Ns60
Ns80
Ns100
Ns175
Ns250

4. 4Pump hydraulic efficiency
Courtesy of Jim Bryan
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY
0.0
20.0
40.0
60.0
80.0
100.0
120.0
0 20 40 60 80 100 120 140
(Q/Q_oo) x 100
(eff/eff_oo)x100
Ns = 21.0224 or
Nsus = 1086.0177

5. 5Pump hydraulic efficiency
From Karassik chapter 2
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

6. 6Pump hydraulic efficiency
21333.0
08955.0
−
⎥⎦
⎤
⎢⎣
⎡
×× X
N
Q
2
10
2286
log29.0 ⎥
⎦
⎤
⎢
⎣
⎡
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
×
sN
94.0(a) (b) (c)
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

7. 7Pump hydraulic efficiency
Calculated by equation
(44) where X=1
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

8. 8Pump hydraulic efficiency
An alternative method is developed in order to link efficiency
with rotating speed, volume flow rate and specific speed based
on Figure 10.
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

9. 9Pump hydraulic efficiency
Base curve
Shift factor
( )⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
×−−= s
s
N
N
ln0663839.0
53047.228
016280719.0expη
063716822.0
99995568.037174634.0 s
N
Ns
××=η
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

10. 10Pump hydraulic efficiency
For 200 < Ns < 2000
( )⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
×−−= s
s
N
N
ln0663839.0
53047.228
016280719.0expη
Base curve
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

11. 11Pump hydraulic efficiency
For 10000 > Ns > 2000
063716822.0
99995568.037174634.0 s
N
Ns
××=η
Base curve
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

12. 12Pump hydraulic efficiency
Base curve
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

13. 13Pump hydraulic efficiency
21333.0
08955.0
−
⎥⎦
⎤
⎢⎣
⎡
×× X
N
Q
Shift factor
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

14. TURBO GROUP – PUMP HYDRAULIC EFFICIENCY
Shift factor
Pump hydraulic efficiency 14
Shift factor vs Q/N
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.001 0.01 0.1 1 10 100 1000 10000 100000 1000000 10000000 1E+08 1E+09
Q/N
Shiftfactor
The exponential of the graph is from
21333.0
08955.0
−
⎥⎦
⎤
⎢⎣
⎡
×× X
N
Q

15. 15Pump hydraulic efficiency
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

16. 16Pump hydraulic efficiency
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

17. 17Pump hydraulic efficiency
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

18. 18Pump hydraulic efficiency
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

19. 19Pump hydraulic efficiency
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

20. 20Pump hydraulic efficiency
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

21. 21Pump hydraulic efficiency
These efficiency curves resemble
Figure 10 (Karassik, chapter 2).
TURBO GROUP – PUMP HYDRAULIC EFFICIENCY