Hi All,

Im currently trying to model an impinging jet of air onto a cylinder at constant temperature. Im interested in the heat transfer coeffiecent ditribution on the cylinder. The results Im getting don't match experimental result though. The stagnation point has the lowest heat transfer coefficient in the simulation but experimentally it is the highest.

I've also tried to simplify the situation by modeling cross flow over a cylinder and still the heat tranfer coefficent distribution doen't match published exprimental results. The heat transfer coefficient at the stagnation point is still very low relative to other parts of the cylinder.

What could I be doing wrong?

Any help would be appreciated.

Thanks

Dan Laurin

Is keeping the cylinder temperature constant physically reasonable? Heat transfer from the cylinder to the fluid (or visa cersa) implies a temperature gradient in the cylinder.

Hi Joe,

I haven't actually used a solid domain for the cylinder, only a fluid domain with a cylindrical wall since Im only concerned with the convective heat transfer coefficient. Also, it is only a steady state solutions so I figured it is an instant in time. But I could try using a heat flux boundary condition instead. Thanks for your input.

Dan

There are an endless number of numerical possibilities to explain the differences. Poor boundary layer resolution etc.

You'll need to provide much more information to get a usefull response.

There is a very good heat transfer validation report from CFX which includes such a case. You can download a copy from the CFX Community site at http://www-waterloo.ansys.com/commun...orts.asp?id=11.

Regards, Robin

Thanks Robin,

I just applied for a cfx community membership, hopefully it comes through quickly. Thanks for your help

Dan