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Vashishth Patel December 2, 2008 10:45

CFX turbo - Mass flow rate
Hi guys, Small and stupid question The mass flow rate selection in the boundary template. For a impeller with three blades I know the total mass flow rate at outlet (i.e. 9 kg/s) for entire cylindrical tube containing three blades impeller

However, In turbo mode only one blade is displayed! So what to use for Mass flow rate per component - 3 kg/s (because one blade component is 1/3 of entire body)? or do i use mass flow rate per component - 9 kg/s (because the component shown is in reality the entire 3 blade assembly)

Thanks in advance!


CycLone December 2, 2008 11:15

Re: CFX turbo - Mass flow rate
If you enter the total mass flow rate, Pre will calculate the per-component flow rate and enter it appropriately. If you choose the per-component option, put the per-component value. You can always check the mass flow rate on the actual b.c. after.


Vashishth Patel December 2, 2008 11:34

Re: CFX turbo - Mass flow rate
thanks CycLone! How to check all the values in POST such as mass flow rate, pressure, etc? thanks again

CycLone December 2, 2008 13:19

Re: CFX turbo - Mass flow rate
You can use the function calculator or evaluate an expression, such as "massFlow()@outlet".

When you go through turbo-pre, you can check the applied mass flow rate in the boundary condition review pane. You can also drop into General Mode at the end and review your boundary conditions there.

Running through some of the basic CFX tutorials will help you understand.


manpreet April 2, 2014 13:04

What does it mean by mass flow per passage or per component
Hello Guys,
I am Manpreet Singh. I have to put outlet boundary condition i.e mass flow rate. The value for it is 13.899996 kg/sec. If I divide this mass flow rate for my model i.e NASA Rotor 37 having 36 blades. Then It would be 0.386111 kg/sec. What should I put in ANSYS PRE during boundary condition input . Either o.386111 kg/sec per passage or 0.386111 kg/sec per component.
Thanks and Regard
Manpreet Singh

brunoc April 2, 2014 17:40

I'm guessing you're using the Turbo Wizard mode inside Pre. If you set the number of passages in your model correctly (that is, if Pre understands you have only 1 blade from 36 on the complete rotor) just use 13.899996 [kg/s] with the option 'Per Machine'. Pre will adjust the value for you.

manpreet April 3, 2014 16:54

Thanks Brunoc.
Is it ok if I use mass flow rate i.e 13.89990/36 per component .
Whats your suggestion.

brunoc April 3, 2014 20:33

Yes, you can. On both cases CFX you convert the value to the mass flow for the number of blades you're modelling.

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