Problem with results (heat transfer)

Project Support
1

Hello everyone.

This is my first simulation here. I try to simulate a heat tranfer between a heat surce and a water cooled copper profil. The value for the heat source is 4000W. The water speed ist 0,75m/s. (400l per hour)

The temperatur diffrence between inlet and outlet is just 1 degree. Thats to low. (something around 9 degree would be right) The heat source has also a to low temperture.

I thing a have i bug in my workflow.

2

Hey there, and welcome to the forum!

I agree with you that results don’t look ok. I would expect a higher temperature drop on the fluid.

Here are some aspects that I would improve:

  • The copper material might have too low conductivity, please try different values for this parameter.
  • Finer mesh, especially to better capture gradients across the thin wall of the heat source and the fluid duct.
  • Allow to run for more iterations, so that residuals can get lower (2k to 3k is a good starting point). Below 1e-3 for the highest residual should be acceptable.
  • Try the Conjugate HT v2.0 solver.

I will tag here my colleague @RicardoParis who might be able to give deeper insides in the physics.

3

Hi,

CHTv2 would definitely help here with convergence. On a side note: it’s very likely that the simulation results are not yet converged.

I’d highly encourage you to set result controls, especially an area average at the outlet. From the residuals alone, I cannot tell for sure if the parameters of interest are still shifting.

This page should provide you more insights: How to Check Convergence of a CFD Simulation? | SimScale

Cheers

4

Thanks for your answer.

I done a new project. SimScale

The result in the post process looks better. I think i need some additional iterartion to improve the result.

In the post process i want to check the surface statistic. But i can only pick the volume of the model.
I did reset the result view and reset the solution field.

5

Hi,

Have you already tried hiding all cell zones and only maintaining the walls (i.e. default region) visible?

image
image1321×799 89 KB

It should allow you to select faces.

Cheers

6

ah …that works

Thanks very much.