Question about porous media model

Glenn Price

I am about to model the transient flow through a packed bed using FLUENT 5.

As noted in the user manual, the fluid does not accelerate as it moves through the medium because the volume is 100% open and the porosity is not physically represented. Unfortunately, we are interested in the transit time through the bed which is clearly impacted by this limitation.

Now for my question, what is the best way to model this situation. One possibility is to reduce the thickness of the bed to yield the correct transit time + adjust the bed parameters to get the correct pressure drop. Any other suggestions?