tube-in-tube
 

Hi all, im brand new to CFD. Im trying to model a tube-in-tube heat exchanger using fluent 6.1. The tube is very long and then with fully turbulent flow. Can anyone give some insight as to what kind of turbulent model, mesh and wall treatment to use?

thanks alot Andrew

Re: tube-in-tube
 

Do you want to simulate heat transfer too and also conjugate heat transfer.

Re: tube-in-tube
 

yes. one tube has air entering at 400k and the other, air at 1300k

Re: tube-in-tube
 

In case of conjugate heat transfer ..., remember never to use k-epsilon turbulence model, it overpredicts the heat transfer. As you are using Fluent, you can specify velocity directly as inlet condition, outlet you can specify as pressure-outlet. As far as turbulence intensity and length scale are concerned you can use corelations given in Varstegee and Malansekara (hope I have spelled it correctly) for pipe turbulent length scale. I hope with this you can solve your problem.

Regards

Apurva