thermal analysis with radiation problem

I've just sent you an email.

Thank you for spending some time looking at this for me.


Joe

Duplicated post deleted.<br /><br />Post edited by: Joe Dowsett, at: 2010/07/16 15:07

I don't see what is the problem, everything works fine. May be You make confusion between a stationary and a transient thermal analysis?

I add - for use of all Forum visitors - a simplified mesh (same geometry, but only 2 HEX8-elm), a .comm for stationary and a .comm for transient analysis. The (also added) output-files .mess, .resu are for the stationary case. Min- and Max-Temp are 30.1888°C at the radiating face and 30.2054°C at the heat-loaded face.

In the transient .comm-file I applied Your initial-temperature of 39.809°C. The analysis calculates only the first 6 seconds of the transient behaviour. This time range is very short, that's why after these 6 sec You don't get the equilibrium solution. I didn't do an analytical calculation, but the temperatures seem plausible.




I hope, I helped You. Best regards,
Johannes Ackva

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Thank you!

I'm quite confused as to why the my transient comm didn't work, the only difference I can see is in the result part.


But yes, a stationary analysis was what I wanted. Early on I got an error telling me to look at the increment so I investigated that rather than realising I needed to add the Stationaire command.



Thank you very much for your help, it is very much appreciated.


Joe

Well, it seems I wasn't being entirely stupid.

I've now configured my actual model, fixed flux in, then two different exchange surfaces and also radiation. I can't see why there shouldn't be a stationary state for almost any possible choice of coefficients.

However I'm finding that it's temperamental with regards to a transfer coeff (which I don't actually know the value of hence want to analyse a range).

Likewise the transient one is throwing errors.



Anyway, thanks again, at least I've got some results to work from and can hope fully now better understand what's going on.