[JianT88]

Hi all,

I'm working on a case with conjugate heat transfer using pressure coupled pseudo transient as solution control. My case contains four cell zones: two fluid zones (1 stationary & 1 rotational frame, incompressible ideal gas) and two solid zones(one of them has a heat source, solid is aluminum and piece-wise temperature depended heat capacity). I'm running a steady state simulation and meanwhile monitoring specific surfaces to check if the heat transfer has reached steady state. All relevant surfaces have coupled/via system coupling as thermo boundary condition.

My question is a problem I've observed: sometimes, in one case, the temperature(monitored) increases pretty fast (around 20 deg for one iteration), sometimes it increases extremely slow (about 0.1 deg for one iteration), and both are running under the same case file so I don't think there's any differences of the settings. A very slow temperature increase will result to a much more computational cost.

I'm not using any UDFs, it is a quite straight-forward model. I wonder if you guys has seen similar cases and have any ideas what is really happening behind this? Thanks!

Best Regards,
Jian