CFX-Net Head Gain Calculation

fatih06 · December 30, 2020, 15:03

Hello,

I am currently designing a pump that is from CFTurbo. To analyze it I am using CFX but when I get results in the expression tab I cannot see the net head gain.
So I decided to create my own expression but I failed.
This my expression
(massFlowAve(Total Pressure)@volute outlet-massFlowAve(Total Pressure)@R1 Inlet)/(1050*9.81)
So how can I achieve to define it?
Or is there any solution it to solve automatically?

Thank you.

Gert-Jan · December 30, 2020, 17:59

Why do you think it failed? Did you get an error or warning?

fatih06 · December 30, 2020, 18:15

Quote:

Originally Posted by Gert-Jan

Why do you think it failed? Did you get an error or warning?

for example increasing the mass flow rate should result in decreasing the net head gained.
In the parametric study I chose 5 design points in 3 of 5 trend is like that but after 6L/min it suddenly increases and continue like that

Gert-Jan · December 31, 2020, 05:34

It is difficult to say what went wrong. It could be anything. It depends a lot on how you have setup your case.
Are you convinced it has converged? Do you monitor this equation during the solving process?

December 30, 2020, 15:03	CFX-Net Head Gain Calculation	#1
fatih06 New Member Join Date: Dec 2020 Posts: 2 Rep Power: 0	Hello, I am currently designing a pump that is from CFTurbo. To analyze it I am using CFX but when I get results in the expression tab I cannot see the net head gain. So I decided to create my own expression but I failed. This my expression (massFlowAve(Total Pressure)@volute outlet-massFlowAve(Total Pressure)@R1 Inlet)/(1050*9.81) So how can I achieve to define it? Or is there any solution it to solve automatically? Thank you.

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December 30, 2020, 17:59		#2
Gert-Jan Senior Member Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,913 Rep Power: 28	Why do you think it failed? Did you get an error or warning?

December 31, 2020, 05:34		#4
Gert-Jan Senior Member Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,913 Rep Power: 28	It is difficult to say what went wrong. It could be anything. It depends a lot on how you have setup your case. Are you convinced it has converged? Do you monitor this equation during the solving process?