LONG POST TO FOLLOW

My company uses a great deal of IGBT and SCR's where the junction temps is critical to the survival of our power conversion units. (I have attached a cut sheet to one of our more common parts)

My quandary is in how (in the heck) to model these parts in FLOW because we do not have any specific material data from the component manufacturer. In most cases, they provided us with (highly suspect) thermal resistance coefficients between junction and case and between the case and the heatsink.

For those of you still reading this....good on you and thanks..... I can empirically measure the temp at the base of the component sitting on top of the heat sink and the case of the device. But, I have to backward calculate the temp of the junction which is not hard. But, I want to be able to use flow to predict the temp of the case because these little buggers and others like them are mounted such that convective flow heats the component mounted above it.

SO.............

My original thought was to take our existing SWx models, used as space claims, and make them multi-body. From there I can apply a material to the metal  base (no big deal) but I have no idea what the material of the case is. This means I would have to keep futzing with a user created material until I get a case temp in FLOW that matches what we measure real world.

Can anyone else think of a better (spelled e-a-s-i-e-r) way to do this?