Internal fan simulation

hokhay · May 31, 2019, 00:24

Hi all,

I am trying to simulate a electronic cooling case which contains a small centrifugal fan. I first want to make the fan works before adding the electronic components.

Since the inlet and the outlet shape of the fan are different, the fan BC which only works for cyclic patch does not work in this case. However the material that I can find from the tutorial and this forum are all about cyclic BC.

Could anyone show me the correct procedure of doing this kind of simulation please? I have attached the picture of the fan. The red patch is the inlet and the green one is the outlet.

Thank you

hokhay · June 2, 2019, 21:37

Any response will be appreciated. Thank you

tomf · June 3, 2019, 04:10

Hi,

Maybe fanPressure can help you out?

I did not use this one myself, but it seems like it can do what you want?

Regards,
Tom

hokhay · June 7, 2019, 23:01

Quote:

Originally Posted by tomf

Hi,

Maybe fanPressure can help you out?

I did not use this one myself, but it seems like it can do what you want?

Regards,
Tom

Thanks for your reply Tom, i have looked at acuPressure but it seems it is not a coupled BC. I have seen others using it and the mass flow rate at inlet and outlet are different.

Please correct me if I am wrong

hxaxtma · June 11, 2019, 03:30

It is not 100% percent clear to me what you really want to achieve.

1) Do you want to model the fan by kind of actuator disk then no interfaces are needed:
see http://www.tfd.chalmers.se/~hani/kur...ningReport.pdf

2) If you want to resolve your fan geometry by an MRF zone in steady or transient you need to use cyclicAMIs with interfaces at inlet/rotor rotor/outlet. For both variants you could use cyclicAMIs

3) Next, with it comes to interfaces, your AMI weighting factors should be near 1, so please make sure that your mesh is conform at the interfaces.

4) I recommend a "two/three-level" snappyHexMesh (or cfMesh) approach. Which means, first create the fan mesh within your rotating box. Next create a mesh for your farfield (volute or anything and or inlet). And merge those two meshes. Please make sure that you set the cellLevel discretization at the interfaces for all meshes the same.

5) Have a look at the TCFD CFD Support Tutorials. You do not need two use their software suite, but the basic OpenFOAM setup is a good starting point.

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June 2, 2019, 21:37		#2
hokhay Member Join Date: Nov 2014 Posts: 92 Rep Power: 11	Any response will be appreciated. Thank you

June 3, 2019, 04:10		#3
tomf Senior Member Tom Fahner Join Date: Mar 2009 Location: Breda, Netherlands Posts: 634 Rep Power: 32	Hi, Maybe fanPressure can help you out? I did not use this one myself, but it seems like it can do what you want? Regards, Tom

June 11, 2019, 03:30		#5
hxaxtma Senior Member Join Date: Jan 2014 Posts: 179 Rep Power: 12	It is not 100% percent clear to me what you really want to achieve. 1) Do you want to model the fan by kind of actuator disk then no interfaces are needed: see http://www.tfd.chalmers.se/~hani/kur...ningReport.pdf 2) If you want to resolve your fan geometry by an MRF zone in steady or transient you need to use cyclicAMIs with interfaces at inlet/rotor rotor/outlet. For both variants you could use cyclicAMIs 3) Next, with it comes to interfaces, your AMI weighting factors should be near 1, so please make sure that your mesh is conform at the interfaces. 4) I recommend a "two/three-level" snappyHexMesh (or cfMesh) approach. Which means, first create the fan mesh within your rotating box. Next create a mesh for your farfield (volute or anything and or inlet). And merge those two meshes. Please make sure that you set the cellLevel discretization at the interfaces for all meshes the same. 5) Have a look at the TCFD CFD Support Tutorials. You do not need two use their software suite, but the basic OpenFOAM setup is a good starting point.