Charge air system modeling

Lars Ola Liavåg

Dear all,

I am currently modeling the charge air system of a medium speed diesel engine, and my model comprises of the ducting between the turbocharger compressor and the cooler, the charge air cooler itself, and the ducting between the cooler and the air receiver/manifold. The cooler insert is modeled by means of a porous material with properties chosen to match a measured pressure drop, and the cooling is accounted for by a volumetric heat sink implemented in subroutine SORENT. I have a couple of questions regarding this kind of problems:

First of all, I've used the standard approaches for the thermal and turbulence properties of the porous material, but I'm not quite certain whether this is correct or whether the effects of altering the approach will be significant. Can anybody advice me on how to model these properties correctly for CAC applications?

Second, the inlet of my domain is the outlet of the turbocharger compressor, and the flow in this location has a high axial velocity as well as a strong swirl component. Can anybody tell whether it's worthwhile putting down some effort in supplying a more realistic swirl profile (e.g. a Bessel function) than the simple solid body rotation catered for in the BC panels of PROSTAR?

Best regards,

Lars Ola