Seek some guidance on boundary

Hi developer,
I have two questions to ask: to monitor the number of particles injected through the inlet and the number of particles escaping through the outlet. 2.Whether the outlet boundary can only pass through the particles and block the gas. The mfix version is 22.3.
Thanks so much!

For the monitor:

Go to the Monitors pane, and click on the + to create a new monitor.

Select Particle data and the region of interest. Note that you can have multiple monitors defined at the same time.

The defined monitor will look like this:

You can change the filename, write interval, etc, as well as enable time-averaging.

For the outlet, note that a Mass outflow boundary allows you to set different properties for each phase:

you could set the velocities or flow rate for the fluid to 0:

Another option may be to use one of the various types of semipermeable surfaces available under Internal surfaces:

Hope this helps,

– Charles

Great. Your suggestions are very helpful. Thank you!!