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Flow across a semi-permeable membrane

Posted May 22, 2015, 2:31 a.m. EDT Fluid & Heat, Geometry Version 4.3b 2 Replies

Aaron Tan
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Hi ,

I am trying to model flow through a semi-permeable membrane due to a pressure gradient. For now, I am using free and porous media flow physics and for my geometry, I have set up 3 rectangles next to each other. The middle rectangle has been designated to be the porous material, and the rectangles on the ends are the fluid materials.
Am I approaching this problem correctly with COMSOL? If not, what is the best way to approach this? How am I suppose to specify 2 separate pressures on both sides of the membrane to drive fluid flow across the membrane?

Thank you so much,
Aaron
2 Replies Last Post May 23, 2015, 6:59 a.m. EDT
Aaron Tan
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Posted: 9 years ago May 22, 2015, 3:24 p.m. EDT
Update:
I tried applying laminar flow and transport of dilute species physics. For the geometry, I created an assembly with 2 squares next to each other and set the contact point in the middle as a flow continuity. This boundary is my membrane. I tried setting an equation for the flux at that boundary using the pressure difference (J= hydraulic conductivity * Pressure difference).

I still have no success however.
Update: I tried applying laminar flow and transport of dilute species physics. For the geometry, I created an assembly with 2 squares next to each other and set the contact point in the middle as a flow continuity. This boundary is my membrane. I tried setting an equation for the flux at that boundary using the pressure difference (J= hydraulic conductivity * Pressure difference). I still have no success however.
Lasse Murtomäki
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Posted: 9 years ago May 23, 2015, 6:59 a.m. EDT
Let's say that the velocity variables of the liquid flow is u, v and w in the flanking domain. Then in the porous domain use leaking wall boundary condition, setting these variables the boundary values.

Attached my model which I did some time ago. There a flow is hitting a porous plug.

br Lasse
Let's say that the velocity variables of the liquid flow is u, v and w in the flanking domain. Then in the porous domain use leaking wall boundary condition, setting these variables the boundary values. Attached my model which I did some time ago. There a flow is hitting a porous plug. br Lasse

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