two fluid flow
 

Hello;

I will solve a problem that is a conjugate heat transfer. There are two fluid;

air and water. The flow is cross-flow (unmixed). When I define air as domain

fluid, Phoeics defines density of water the same as air , too. In fact water

enters 60 °C and 0.295 kg/s. Air enters 1717 °C and 0.011. So , how can I

define this statement ?