Pump efficiency curve - 8th October 2009

Pump Hydraulic Efficiency

Prediction of efficiency curves30th September 2009Prepared by: Cheah CangTo

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

Hea

d-m

/Eff-

%/k

W

0.0

0.5

1.0

1.5

2.0

2.5N

PSH

met

res

Head Eff kW Rated Point NPSH

Courtesy of Jim Bryan

Efficiency curve

TURBO GROUP – PUMP HYDRAULIC EFFICIENCY

Volume flow rate (m3/hr)




0

20

40

60

80

100

120

0 20 40 60 80 100 120 140

(Q/Q_oo) x 100

(Effi

cien

cy/E

ffici

ency

_oo)

x 1

00

Ns20

Ns40

Ns60

Ns80

Ns100

Ns175

Ns250




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)

x 1

00

Ns = 21.0224 or

Nsus = 1086.0177


From Karassik chapter 2



21333.0

08955.0−

⎥⎦⎤

⎢⎣⎡ ×× XNQ

2

102286log29.0 ⎥

⎦

⎤⎢⎣

⎡⎟⎟⎠

⎞⎜⎜⎝

⎛×

sN94.0(a) (b) (c)



Calculated by equation (44) where X=1



An alternative method is developed in order to link efficiency with rotating speed, volume flow rate and specific speed based on Figure 10.



Base curve

Shift factor

( )⎟⎟⎠

⎞⎜⎜⎝

⎛×−−= s

s

NN

ln0663839.053047.228016280719.0expη063716822.099995568.037174634.0 s

N Ns ××=η



For 200 < Ns < 2000

( )⎟⎟⎠

⎞⎜⎜⎝

⎛×−−= s

s

NN

ln0663839.053047.228016280719.0expη

Base curveTURBO GROUP – PUMP HYDRAULIC EFFICIENCY


For 10000 > Ns > 2000063716822.099995568.037174634.0 s

N Ns ××=η

Base curve



Base curveTURBO GROUP – PUMP HYDRAULIC EFFICIENCY


21333.0

08955.0−

⎥⎦⎤

⎢⎣⎡ ×× XNQ

Shift factor



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

Shift

fact

or

The exponential of the graph is from

21333.0

08955.0−

⎥⎦⎤

⎢⎣⎡ ×× XNQ














These efficiency curves resemble Figure 10 (Karassik, chapter 2).


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Pump efficiency curve - 8th October 2009