Density change in channel
 

Hi! i want to start my work on fuel cell modeling with matlab.

But when I consider flow in channel, i have a confusion about density issue.

Although velocity of hydrogen gas flow is slow, there exist considerable pressure

gradient because of hydrogen mass reduction through membrane.


Should i consider gas as compressible one with density change?

I don't know what to do because my origin major is not that related with CFD.

Now I have knowledge about only incompressible viscous flow.

Can i get some examples of code about CFD with density change or some advice?