Simulation run

Project Support
1

hi, i have a problem when i go to simulate my mesh. when I start the simulation it stops immediately warning me with a message “Maximum number of iterations exceeded when calculating temperature from a thermodynamic potential. This may be caused by low-quality mesh producing unrealistic pressure in a few cells or inappropriate boundary conditions, fluid properties or time step. Inspect fields for large values in the last time step.” if you can help me thank you in advance. my project is this:https://www.simscale.com/workbench/?pid=7074487650232377579&mi=run%3A417%2Csimulation%3A360&mt=SIMULATION_RUN

2

Thank you for using SimScale Forum!

Looking at your project, a few things have come to my attention.

I could recommend you to review your Velocity inlets and Pressure outlet air boundary conditions. 122 kg/s mass flow rate of air will result in around 2300 m/s (around 6-7 times of speed of sound) of velocity with a 0.25 m diameter inlet which doesn’t seem applicable. You can adjust your mass flow rate at your inlets considering the density of your material (air in your case) , or use fixed value for your velocity to avoid such issues.

Are you using Kelvin or Celcius for temperature at your boundary conditions? If those values are in Kelvin, you can change it by clicking on the unit next to the temperature value.

For your application you can refer to this following tutorial. Be aware that in this tutorial, air and water is used for two different flow regions.

Hope this helps.

3

I am doing a simulation for a realistic industrial process so the mass conditions and temperatures (I entered them in degrees celsius) are those of the process.

4

Hello again, thank you for informing. If the error continues with changes in boundary conditions, there are a few more things that you can try to obtain convergence for your simulation.

  1. You can try changing the mean flow rate velocity type to flow rate type. This sometimes causes stability issues in certain conditions.
  2. You can further increase the quality of your mesh. Overall quality seems good, but there are a few cells with a very high nonOrthogonality, and aspectRatio. You can detect these cells by using Mesh Quality option on the Mesh tree.
    How to Check and Improve Mesh Quality | SimScale
  3. You can ramp up your boundary conditions by using tables. This will ramp your values up at your boundaries, consequently increasing the stability of your simulation.
    Tables | Boundary Conditions | Documentation | SimScale

Hope these help.