Need help : porous media for heat exchanger
 

I am modeling a porous media, where few tubes of water flow was embedded in the media, and the air will flow through it too. Through the porous media, the air is able to exchange the heat with water.

However, I am facing big problem of defining the heat exchanging properties. I modeled the air + porous as one domain, and adding a subdomain in the porous region. In the subdomain, I can input porous loss, but I don't know how I can input the properties so that the heat exchange between air/porous/water_tubes. I wm not even sure if CFX 5.7 can do this.

Can anyone please kindly help me on this ?

Regards X. Shen