heat convection in a forced fluid
 

I want to simulate a cooler whit COMSOL 3.2

I have a 3D body of alluminium, into that there is a water circuit. on a face of the cooler there is a heat flux due to the body that i want to cool.

I force the presure of the water at 1.2 atm. With Navier-stoke model I can solve the velocity of the fluid in all three direcion (vx,vy,vz).

With the General heat transfer module I discribe the heat conduction and convection phenomena of the alluminium body and of the fluid coduciont and convection.

In the Convection shell I force the the x, y, and z velocity whit the value of vx, vy, vz soved whit the Navier Stoke model, by i have same propblem of convergence.

In general i have problem with convection module also if i force the velocity of the convective shell with a constant.

anyone can help me?

there is an oder way to simulate a cooler?

thank.