Efficiency prediction of centrifugal pumps in CFX

peiji1984 · August 1, 2014, 08:18

Dear all,
I have done a lot of simulations for centrifugal pumps in CFX, and I found that the efficiency prediction (ρgQH/Mω) is not accurate, especially for a centrifugal pump with very large flow rate as design point, for example, 10000 cubic meter per hour. At design point, the head result is acceptable, but the efficiency result is obviously lower than the test data. Does anybody have the experience about this? I will be very appreciated if you can explain to me.
Thanks a lot!
Ji

Ahmedelshetiry · November 19, 2022, 03:23

I have the same problem. Did you get any solution?

zacko · November 19, 2022, 09:24

How are you computing the Moment ? I assume you use the torque variable in Post of blade, hub and shroud ? Are you modeling the side chambers ? This is obviously a simplification which will result in a difference in test data and simulation data. But, in my experience, the Efficiency would be higher then (without side chambers).
By which magnitude do the test data and CFD result differ ?
Convergence was reached, correct ? Is the mesh accurate enough ?
Are you evaluating your hydraulic data at a similar position like the test data, e.g. suction and discharge pipe position ?

August 1, 2014, 08:18	Efficiency prediction of centrifugal pumps in CFX	#1
peiji1984 New Member Ji Pei Join Date: Nov 2010 Posts: 8 Rep Power: 15	Dear all, I have done a lot of simulations for centrifugal pumps in CFX, and I found that the efficiency prediction (ρgQH/Mω) is not accurate, especially for a centrifugal pump with very large flow rate as design point, for example, 10000 cubic meter per hour. At design point, the head result is acceptable, but the efficiency result is obviously lower than the test data. Does anybody have the experience about this? I will be very appreciated if you can explain to me. Thanks a lot! Ji

November 19, 2022, 09:24		#3
zacko Senior Member Daniel Join Date: Feb 2017 Location: Germany Posts: 147 Rep Power: 9	How are you computing the Moment ? I assume you use the torque variable in Post of blade, hub and shroud ? Are you modeling the side chambers ? This is obviously a simplification which will result in a difference in test data and simulation data. But, in my experience, the Efficiency would be higher then (without side chambers). By which magnitude do the test data and CFD result differ ? Convergence was reached, correct ? Is the mesh accurate enough ? Are you evaluating your hydraulic data at a similar position like the test data, e.g. suction and discharge pipe position ? Last edited by zacko; November 19, 2022 at 20:06.

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November 19, 2022, 03:23		#2
Ahmedelshetiry New Member Ahmed mohamed Join Date: Oct 2022 Posts: 1 Rep Power: 0	I have the same problem. Did you get any solution?