Simulation crash at high heat load

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I am trying to simulate air conditioning of a substation using convective heat transfer.
When I run it with the equipment heat load of 10 kW then the simulation works fine.
But when I increase the equipment heat load in the room to 400 kW then simulation crashes. (it crahes even at 20kW heat load) … Why…?

Please help?

Link: millsub by t3s | SimScale

Thank you for posting on the forum. Let me have a look and I will get back to you :slight_smile:

From the errors, it seems you have a velocity divergence issue.

To help users identify and troubleshoot divergence in their simulations, SimScale has a divergence monitor. The following parameters are tracked: velocity, pressure, density, and temperature. Whenever a parameter reaches unrealistic levels in the domain, the simulation automatically stops with an error message:

The error message specifies which parameter diverged and also the exact location in the model. This information is valuable and can be a starting point for the troubleshooting process.

To gain more insight into the causes of divergence, the following basic steps are useful:

  1. Create a ‘probe point‘ result control and input the coordinates displayed in the error message. In doing so, you will see exactly where the divergence occurred;
  2. If the point is close to one of the boundaries, double-check all boundary conditions, making sure they are correct;
  3. If the point is located inside the domain, inspect the mesh around the area. The ‘mesh quality ‘ visualization feature is very useful in this step. Even just a few bad quality cells can create instabilities in the simulation, ultimately leading to divergence.

If you want to learn more and have a look at some trouble-shooting examples too, make sure to read this article:

Divergence in Simulation: How to Tell When and Where? | SimScale

This article explains how to detect divergence in a simulation and provides common troubleshooting workflows.

Thank you for your reply!
I have a question though, if the mesh quality is bad, why does it work when I input the equipment heat load lower? Shouldn’t that also crash?