UDF for 3rd Kind Boundary Condition
 

Hi, everybody:

I am a recent Fluent user. I need urgent help for defining the heat transfer coefficient at a boundary wall which is dependent on the adjacent cell temperature, using a UDF.

Consider a cylindrical rod into which heat flows through its ends, and cools via natural convection on its lateral surface. I want to solve the conduction problem in the rod, and specify the temperature of the adjacent fluid and the heat transfer coefficient as the boundary condition on the lateral surface.

Since the heat transfer coefficient is dependent on the temperature difference between the surface and the fluid, I have to define this dependency through a UDF so that FLUENT can re-calculate the heat transfer coefficient at every iteration with the new temperatures.

Can anyone provide me such a UDF or refer to a source that contains it?

Thanks in advance..

Re: UDF for 3rd Kind Boundary Condition
 

If you take a look at the UDF user manual (chap. 4.3.5) you should be able to construct your UDF from the examples.

Dear Ismail,

Have you solved this problem ?
Even it is posted about 10 years ago, i still hope that the good news can be got from you .

Thanks and best regards

Yu Qiu