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 JB October 17, 2006 23:22

Heat Transfer Problem Help

I am trying to set up a simple heat transfer problem and am running into problems and need some help. I am trying to create a simple cylinder and apply a heat flux to the top of the cylinder. I then want to look at the temp. gradiant and I expect to see something along the lines of higher temps. closer to the top with the temperatures getting lower as you move down the cylindrical plate.

I have no problem creating the geometry and meshing the plate. Where i think i am running into problems is boundary conditions or maybe setting the problem up in Fluent. Here is what I did:

I created boundary conditions of "wall" along all the edges: top, side, and bottom. I also specified the continum type as a solid.

Exported the mesh and can bring into Fluent with no problems. I turn on the energy equation in the define models. At the top wall boundary conditions I apply Heat flux, wall thickness, and heat generation rate. Set up to solve and it will iterate until convergence. Problem I have is when i look at the temp. gradiant there is uniform temperature throughout the piece. So something is not right and I could use some help.

-Jason

 Ryan October 18, 2006 01:53

Re: Heat Transfer Problem Help

Hi Jason,

If it is a cylinder and you are modelling the flow around it. There is no need to create a solid zone.

Create a big cylinder around your smaller one representing the fluid domain.

Subtract the smaller cylinder from the bigger one.

The surfaces representing the smaller cylinder just subtracted will be your region of interest.

Set up as normal you have done until now.

When you say uniform temperature through out the piece do you mean along the vertical cross section of the cylinder.

You need to have boundary layer as well to pick up the minute changes.

Good luck!!

Regards

Ryan

 Pavan October 18, 2006 18:54

Re: Heat Transfer Problem Help

I am not sure if I get you right but what I've read it looks to me like you are solving the problem as a steady state problem and if you are then what you are seeing makes sense. If you solve it as unsteady or time-dependent problem, then you would see a variation in the temperature gradient with time. I hope this solution helps and makes sense to you.

Pavan

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