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-   -   Domain imbalance in CHT (http://www.cfd-online.com/Forums/cfx/101328-domain-imbalance-cht.html)

Studentdrak May 1, 2012 08:22

Domain imbalance in CHT
 
Hi,

I am trying to simulate a simple CHT problem.

I give a constant heat flux the base plate(with certain thickness) and a fin is attached to the base plate(as a integral part of base). Both are made of aluminium.

Air flows over the fin. Interfaces with conservative interface flux has been defined at domain interfaces.

I get a domain imbalance for H-energy for air as ~ 3% !!! and T-energy as ~0.3% .(residuals have converged)

Kindly suggest some ways to improve my soln. asap.

Thanks

stumpy May 1, 2012 09:10

Residuals are not a measure of global conservation. Keep running until the imbalances are reasonable (or use the Conservation Target control).

ghorrocks May 1, 2012 19:14

As stumpy says, you need to include imbalances in the convergence definition. CHT is the key example where imbalances are required to gauge convergence as residuals do not pick up the global imbalance.

If steady state, you probably alos need to use some solid time scale factor as well. This greatly accelerates convergence in CHT simulations.

Studentdrak May 2, 2012 04:21

Thanks stumpy and Glenn.


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