CFD Online Logo CFD Online URL
Home > Forums > ANSYS

Power calculation in centrifugal pump - CFD Post

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree1Likes
  • 1 Post By Evgeniy_IV

LinkBack Thread Tools Display Modes
Old   April 27, 2017, 07:58
Default Power calculation in centrifugal pump - CFD Post
New Member
Join Date: Mar 2017
Posts: 3
Rep Power: 2
Hazem_9 is on a distinguished road
I have made a model for centrifugal pump of impeller speed 2960 rpm using CFX. Inlet and impeller domains meshes are done using Turbo-Grid, while Volute mesh is done using Ansys mesher. I defined the impeller as a rotating domain of speed 2960 rpm, while Inlet and Volute as stationary domains. Boundary condition: flow rate at inlet, static pressure at discharge and all other faces are no slip walls.
The model residuals converges, results are excellent and head performance curve is very near to the experimental curve.

But the problem is that results of shaft power in simulation is half the value of the experimental data ... consequently, the efficiency calculation was overestimated

Power calculated in CFD-post using the following equation
Power = Torque * Rotational velocity = Number of Blades * Blade torque * Rotational velocity

These are the exact expression written in CFD-Post:
  • tBladeRow = torque_z()@Impeller Blade
  • tAllBlades = tBladeRow * BladesNumber
  • Power = tAllBlades * Absolute Omega / 1 [rad]
__________________________________________________ ______________
Moreover, I tried to solve the same pump model at different speeds. I found that:
  • At speed= 1500 rpm --> Shaft power results in simulation half the experimental data value
  • At speed= 2960 rpm --> Shaft power results in simulation is half the experimental data value
  • At speed= 6000 rpm --> Shaft power results in simulation is half the experimental data value

I want to know how to solve this issue to get correct estimation for shaft power and efficiency

Last edited by Hazem_9; April 27, 2017 at 11:37.
Hazem_9 is offline   Reply With Quote

Old   May 11, 2017, 14:22
New Member
Evgeniy Ivanov
Join Date: Oct 2016
Location: Russia, Saint-Petersburg
Posts: 2
Rep Power: 0
Evgeniy_IV is on a distinguished road
Dear Hazem_9
When you use expression which you wrote (Power = tAllBlades * Absolute Omega / 1 [rad]) you calculate only hydraulic effective power for impeller but not for pump.If you want to calculation power pump you must take into account power losses in your gap between disc of impeller and wall of volute and also loss of friction.
Hazem_9 likes this.

Last edited by Evgeniy_IV; May 11, 2017 at 15:34.
Evgeniy_IV is offline   Reply With Quote


centrifugal pump., cfx, efficiency, power, shaft power

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Input power calculation for pump in CFD post Dhairya@CFD CFX 3 April 27, 2017 08:06
Parallel process & CFD POST jypark FLUENT 2 August 14, 2013 23:49
Problem with centrifugal pump calculation Michiel Main CFD Forum 2 June 17, 2012 21:32
Enthalpy calculation in cfd post bharath CFX 0 October 7, 2011 22:14
centrifugal pump cfd analysis shatruhan lal FLUENT 1 November 6, 2003 07:23

All times are GMT -4. The time now is 13:38.