Immersed membrane bioreactor

One-phase simulation

First, the meshgrid without injector must be approved. In this purpose, I have as boundary conditions a inlet-velocity of 1,5 10-4 m.s-1 and a velocity on the membrane of -8,7 10-5 m.s-1 (negative velocity to check the outlet). After a steady computing in laminar flow, Fluent find the following results : (click on the picture to enlarge it)

These results are acceptable because in one hand, the flow is conserved and in the other hand, the calculed velocity is appropriate (increase with the decrease of the section). Nevertheless you can notice that on the top of the box, there are incoming and outcoming velocities. In this case, it causes no trouble (the flow is conserved), but it could cause some in the other simulations. So, we must pay attention to this boundary.