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-   -   How to define fan performance curve in CFX using interpolation function? (https://www.cfd-online.com/Forums/cfx/127925-how-define-fan-performance-curve-cfx-using-interpolation-function.html)

atulpat December 26, 2013 01:49

How to define fan performance curve in CFX using interpolation function?
 
Hello friends...
I am working on HVAC analysis of data center and I have fan performance curve. But I dont know how to define fan performance curve in CFX using interpolation function. Please help me.

Thanks in advance.

ghorrocks December 26, 2013 04:16

How are you trying to implement the fan? As a inlet or outlet, a source term or something else?

atulpat December 26, 2013 07:20

Yet I have not tried but little bit I know that we can implement it at inlet using sub-domain.

ghorrocks December 27, 2013 04:28

You implement it at an inlet OR a sub-domain. You should not do both. You can define an inlet to follow a fan curve, or define a momentum source on a sub-domain to follow a fan curve.

atulpat December 28, 2013 00:48

Thanks Ghorrocks.
Yes you are right. I already worked on data center using sub-domain and it is valid only when air flow from tile is directly going into the respective server rack (i.e. tile exactly located in front of server rack and air flow directly going into server rack). I used following expression for the same case for air flow in +ve X direction
Expression for RACKFAN

massFlow()@REGION:Tile1 / ((1.2 [kg m^-3])*area()@REGION:S_INLET)
and momentum source is

-1E5 [kg m^-3 s^-1]*(u- RACKFAN)

But in most of the cases it is not like that. Hence I am thinking to use Fan performance curve and it is possible to use the curve only by interpolation function. Please help me how we can use this interpolation function. I never used interpolation function that's why I came across this problem.


regards
Atul

ghorrocks December 28, 2013 04:46

The tutorials give examples of interpolation functions (nt sure which one though). Alternately just inset an interpolation object and stick in a few points to see how it works. They are quite simple to use.

atulpat January 1, 2014 07:42

Thanks ghorrocks
If you knows any tutorials then please provide me the links.


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