How to set the imported geometry.stl as a deflector that can block particles and airflow?

There are 16 thin swirl blades in my model, which are quite different from the overall size, so it is difficult to divide the cut mesh. Now I export the swirl blade separately file(.stl), hoping to achieve the impenetrable effect of air flow and particles hitting the blade.

I tried the internal surfaces function, but it doesn’t seem to select the file(.stl) that the user imported. Please kindly learned little friends, is there any way to solve my difficulties?

Hi @chengmin_sheng and welcome to the MFiX forum.

Please attach a ZIP file containing all your inputs (go to main menu and select “Submit Bug Report”). Thanks!