Time dependence pressure values

Hello,
my goal is to simulate a leak in a vaccuum chamber, and to be able to take pressure readings in fractions of a second. I’m doing this by applying an outgassing rate to a facet on my object that matches the leak rate of air flowing in, and by using the time dependent function to track the pressure change. But I’m running into some problems. On my timewise plotter, the pressure is displaying as zero in many places when it should be a non zero pressure, because there is also outgassing on every facet. It looks like on the timewise plotter though, it is picking up on some of the pressure readings near the leak, but that’s it. Do you have any suggestions on how to fix this? I tried playing with the low flux mode, but that did not seem to solve this problem.


Another solution is making the y axis logarithmic. Below is what the plot looks like when I did this. I looks like it captured more values but left out the first and last section of the facet. Also I cannot copy these values to my clipboard for some reason.

Hello Claire, sorry for the slow reply.

It’s hard to find the problem without looking at the geometry or some screenshots of the plotted facets. One guess is that maybe

  • the u/v orientations are not correct
  • the facet is not rectangular,
  • when setting up moments, you used the default 1E-10s time window

If you can share the geometry here or let us know more, I’ll try to find what’s wrong.

We don’t use the low flux mode, it was rather an experiment in Molflow (it’s very effective for synchrotron radiation simulation with specular reflection, but not that much for vacuum simulations with Lambertian reflections).

Cheers, Marton