Energy source and source coefficient

stuart230588 · January 16, 2014, 05:36

Hi,

I am trying to simulate an electrical arc using CFX, which is modelled using the MHD function by applying a voltage difference. However, I am having trouble defining the radiation losses of the arc.

The energy source in the subdomain is being defined as the radiation loss from the arc (data has been taken from previously published literature), which I have converted to be of the form W/m^3 at a given temperature. This has been input using a user function, which is then read as the energy source.

However, I am having trouble defining the subdomain energy source coefficient - how can this be calculated?

Thanks,
Stuart

ghorrocks · January 16, 2014, 07:21

You can have either (Or both) heat sources and radiation sources. What are you using?

Definition of the energy source coefficient is described in the manual. Have you looked it up?

stuart230588 · January 16, 2014, 07:33

I am currently using thermal energy heat transfer model with radiation data being provided as a source term via additional variables. I do not have the thermal radiation model activated.

I have looked at the CFX-Pre user guide which didn't go into much detail on the source coefficient other than its units and that it helps with convergence.

ghorrocks · January 16, 2014, 16:56

The documentation pretty much explains all there is to it. It just helps convergence, does not affect the final converged solution and should be set to the derivative of the source term with the variable it is affecting.

What more do you need to know?

January 16, 2014, 05:36	Energy source and source coefficient	#1
stuart230588 New Member Join Date: Oct 2013 Posts: 25 Rep Power: 12	Hi, I am trying to simulate an electrical arc using CFX, which is modelled using the MHD function by applying a voltage difference. However, I am having trouble defining the radiation losses of the arc. The energy source in the subdomain is being defined as the radiation loss from the arc (data has been taken from previously published literature), which I have converted to be of the form W/m^3 at a given temperature. This has been input using a user function, which is then read as the energy source. However, I am having trouble defining the subdomain energy source coefficient - how can this be calculated? Thanks, Stuart

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January 16, 2014, 07:21		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,701 Rep Power: 143	You can have either (Or both) heat sources and radiation sources. What are you using? Definition of the energy source coefficient is described in the manual. Have you looked it up?

January 16, 2014, 07:33		#3
stuart230588 New Member Join Date: Oct 2013 Posts: 25 Rep Power: 12	I am currently using thermal energy heat transfer model with radiation data being provided as a source term via additional variables. I do not have the thermal radiation model activated. I have looked at the CFX-Pre user guide which didn't go into much detail on the source coefficient other than its units and that it helps with convergence.

January 16, 2014, 16:56		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,701 Rep Power: 143	The documentation pretty much explains all there is to it. It just helps convergence, does not affect the final converged solution and should be set to the derivative of the source term with the variable it is affecting. What more do you need to know?