[dbecker]

Hello,

I am tasked to perform a natural convection analysis on electrical components. I am using CFX 11.0 and ICEM.

Before I began the analysis I wanted to see if CFX is capable of performing this type of analysis. I made a simple cylinder in a box, the cylinder extends to the walls of the box and I put slip planes on the end walls to simulate infinitely long cylinder. I put no slip planes on the sides and top and bottom.

Cylinder is set at 500C and roof and floor and side walls are at 55C. I turned on bouyancy and I am using shear stress transport because ultimately I am looking for heat transfer coefficients on the cylinder.

I ran the solution and this is the result, heat transfer coefficients are about right according to my hand calcs for a cylinder in air with this deltaT, but the gas temperature distribution is almost all uniformly 55C. This is wrong, there should be a spread of temperature between 55 and 500. This does not make sense and I need to know how to validate and run natrual convection models in CFX.

I tried using the help file and there is about 2 paragraphs on the subject and that's it. Does anyone have any experience using CFX for natural convection? Please help!

Thanks,


- D