source on surface.

dzuodoka · April 26, 2011, 09:07

I have HTC on surface and I'd like to add source on it. i.e. function of heat flux. I choose Sources -> Boundary Source -> Sources -> Energy -> Flux and it doesn't work.

Has anybody got suggestions what's going on ?

ghorrocks · April 26, 2011, 21:52

What does not work about it?

dzuodoka · April 27, 2011, 02:56

The heat flux doesn't appear in postprocessor. It seems to be not choosen in pre but it is like I explained.

ghorrocks · April 27, 2011, 19:24

What do you mean "The heat flux doesn't appear in post"? I am not sure about this but your heat flux will not appear in the "Wall Heat Flux" variable. If you want to see how much heat you are applying you have to use an additional variable to output it to the post processor - this is a good idea in development of source terms so you can check the source term is correctly applied.

dzuodoka · May 3, 2011, 14:54

Thanks a lot for your response.

I still have problem with seeing my heat flux source in the post-procesor. Could you write it down more clearly.

Maybe I should put it this way. I have external wall with HTC condition and I would like to ask how to add heat flux source on it ?

ghorrocks · May 3, 2011, 19:16

Quote:

I have external wall with HTC condition and I would like to ask how to add heat flux source on it ?

You should be able to put a source term on the face in CFX-Pre in the boundary tab. Simple.

dzuodoka · May 21, 2011, 07:10

I found out where was the problem. That is, if you add Heat Flux as a boundary condition you get fixed value of heat flux on a surface, but if you add Heat Flux extra to HTC condition as a source you get value changed by heat transfer.

Do you think in that way adding heat flux as a source is appropriate and results will be physically accepted ? I think it is but I'd like to get to know your opinions. Thanks a lot.

ghorrocks · May 21, 2011, 07:58

You set the boundary up to match reality. If HTC is closest then use that. If it is being heated by some external heating use a heat flux. If it has both convection and external heating use convection and a heat flux source term.

dzuodoka · May 30, 2011, 04:08

Quote:

Originally Posted by ghorrocks

....... If you want to see how much heat you are applying you have to use an additional variable to output it to the post processor - this is a good idea in development of source terms so you can check the source term is correctly applied.

Could you explain it more clearly because I don't get it how to aplly this additional variable to see my heat flux source ?

The post processor shows only het flux q=HTC*deltaT and it is clear but I want to display also heat flux source q_source in the post processor.

ghorrocks · May 30, 2011, 06:21

Define a CEL expression as you heat source, then define an additional variable linked to that heat source. Your heat source will now appear int he post procesor under the additional variable.

April 26, 2011, 09:07	source on surface.	#1
dzuodoka New Member Rafał Kryjak Join Date: Jul 2010 Posts: 11 Rep Power: 15	I have HTC on surface and I'd like to add source on it. i.e. function of heat flux. I choose Sources -> Boundary Source -> Sources -> Energy -> Flux and it doesn't work. Has anybody got suggestions what's going on ? Last edited by dzuodoka; May 3, 2011 at 14:15.

April 27, 2011, 02:56		#3
dzuodoka New Member Rafał Kryjak Join Date: Jul 2010 Posts: 11 Rep Power: 15	The heat flux doesn't appear in postprocessor. It seems to be not choosen in pre but it is like I explained. Last edited by dzuodoka; April 27, 2011 at 12:17.

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April 26, 2011, 21:52		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	What does not work about it?

April 27, 2011, 19:24		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	What do you mean "The heat flux doesn't appear in post"? I am not sure about this but your heat flux will not appear in the "Wall Heat Flux" variable. If you want to see how much heat you are applying you have to use an additional variable to output it to the post processor - this is a good idea in development of source terms so you can check the source term is correctly applied.

May 3, 2011, 14:54		#5
dzuodoka New Member Rafał Kryjak Join Date: Jul 2010 Posts: 11 Rep Power: 15	Thanks a lot for your response. I still have problem with seeing my heat flux source in the post-procesor. Could you write it down more clearly. Maybe I should put it this way. I have external wall with HTC condition and I would like to ask how to add heat flux source on it ?

May 21, 2011, 07:10		#7
dzuodoka New Member Rafał Kryjak Join Date: Jul 2010 Posts: 11 Rep Power: 15	I found out where was the problem. That is, if you add Heat Flux as a boundary condition you get fixed value of heat flux on a surface, but if you add Heat Flux extra to HTC condition as a source you get value changed by heat transfer. Do you think in that way adding heat flux as a source is appropriate and results will be physically accepted ? I think it is but I'd like to get to know your opinions. Thanks a lot.

May 21, 2011, 07:58		#8
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	You set the boundary up to match reality. If HTC is closest then use that. If it is being heated by some external heating use a heat flux. If it has both convection and external heating use convection and a heat flux source term.

May 30, 2011, 06:21		#10
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	Define a CEL expression as you heat source, then define an additional variable linked to that heat source. Your heat source will now appear int he post procesor under the additional variable.