Question Regarding Modelling Internal Flow

Alteran · September 4, 2013, 11:55

Hey Guys

Im new to this forum so this is the wrong place for this then I apologise.

My situation:
I am trying to model the air flow through a computer case using Ansys CFX, I have modelled up the computer case in Solidworks, brought it over to CFX and managed to simulate the flow using inlet and outlet boundary conditions for the fans on the outside of the case. now I want to take it a step further and try and simulate the added effects of the internal fans, this is where im having problems. I have the geometry for the internal componets but I dont know how to simulate the effects of the fans on the internal flow, in not interested at this point in time with spiral effect that fans have im perfectly happy with a straight flow normal to the face for the time being. Setting external boundary conditions is straight forward but I dont know how to add internal effects, is this possible, if so could someone graciously tell me how to or point me in the direction of an instructional vid (i have scoured youtube but had no luck).

Additionally im trying to do the same thing using solidworks flow simulation but i have the same problem so any advice here would be helpful also, im using flow simulation as i can add heat sources for the components and see how the flow affects the heat. i know i can do this in ansys but that is WAY beyond my current knowledge of ansys, where as it is relatively simple in SW flow simulation.

This is for a uni project and I am comparing the results of the 2 programs in regards to the air flow

I realise this is a bit long winded and convoluted so once again I apologise for any headaches whilst trying to decipher my problem.

regards

flotus1 · September 4, 2013, 13:07

A very simple approach for the fans could be a momentum source.
In CFX, you can add momentum sources to a subdomain (right-click on the domain, "insert" "subdomain", go to "sources" tab).
All you need is a geometry that represents the fan to add it as the subdomain, but I guess you already modeled it this way.

I dont know about solidflow, but if it should provide a similar option.

September 4, 2013, 11:55	Question Regarding Modelling Internal Flow	#1
Alteran New Member Join Date: Aug 2013 Posts: 1 Rep Power: 0	Hey Guys Im new to this forum so this is the wrong place for this then I apologise. My situation: I am trying to model the air flow through a computer case using Ansys CFX, I have modelled up the computer case in Solidworks, brought it over to CFX and managed to simulate the flow using inlet and outlet boundary conditions for the fans on the outside of the case. now I want to take it a step further and try and simulate the added effects of the internal fans, this is where im having problems. I have the geometry for the internal componets but I dont know how to simulate the effects of the fans on the internal flow, in not interested at this point in time with spiral effect that fans have im perfectly happy with a straight flow normal to the face for the time being. Setting external boundary conditions is straight forward but I dont know how to add internal effects, is this possible, if so could someone graciously tell me how to or point me in the direction of an instructional vid (i have scoured youtube but had no luck). Additionally im trying to do the same thing using solidworks flow simulation but i have the same problem so any advice here would be helpful also, im using flow simulation as i can add heat sources for the components and see how the flow affects the heat. i know i can do this in ansys but that is WAY beyond my current knowledge of ansys, where as it is relatively simple in SW flow simulation. This is for a uni project and I am comparing the results of the 2 programs in regards to the air flow I realise this is a bit long winded and convoluted so once again I apologise for any headaches whilst trying to decipher my problem. regards

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September 4, 2013, 13:07		#2
flotus1 Super Moderator Alex Join Date: Jun 2012 Location: Germany Posts: 3,427 Rep Power: 49	A very simple approach for the fans could be a momentum source. In CFX, you can add momentum sources to a subdomain (right-click on the domain, "insert" "subdomain", go to "sources" tab). All you need is a geometry that represents the fan to add it as the subdomain, but I guess you already modeled it this way. I dont know about solidflow, but if it should provide a similar option.