Porous medium of Filter setting?

[steriopaul50]

Hallo I am a student Thermal engineer for my project I need to simulate a drying cell for potatoes with flows, temperature etc. Simulating a case with potatoes is not an option so I need to make it a new made material or some kind of Filter. 

Specific for a Case of potatoes: per 100m3/product per hour it gives a pressure drop of 100 Pa.

1)With resistance and custom setting I have reached 100Pa. But I did this with Free Area ratio, which is more used for a waffle and stuff not really for a volume. Is the information from this resistance setting trustfully or doesn't it work?

2)In my opinion is it better to have Solid which is porous. Now there is no option for this in CFD(which I have found). I have tried to custom some solids with transmissivity but it doesn't seem to get porous.

Could anybody help me with these two thing

Kind regards,

Paul Moors

[Jon.Wilde]

1)With resistance and custom setting I have reached 100Pa. But I did this with Free Area ratio, which is more used for a waffle and stuff not really for a volume. Is the information from this resistance setting trustfully or doesn't it work?

You can use this setting yes, it sounds as though you already have it working well - just be sure to use a uniform mesh (you might have to coarsen it from the default if the mesh count is huge) in order to properly capture the dP.

2)In my opinion is it better to have Solid which is porous. Now there is no option for this in CFD(which I have found). I have tried to custom some solids with transmissivity but it doesn't seem to get porous - This is what a resistance is, a filter medium. You cannot use a solid material to achieve the same thing, solids are always 100% solid although the transmissivity setting is used to allow radiative heat through - like glass for example.

[OmkarJ]

If I remember correctly, there is a way to define a solid as a porous medium (using material). I had a terrible time meshing it though, as I kept receiving error messages, after which I gave up and started usign the shell resistances (surfaces).

OJ

[Jon.Wilde]

The only way is through using Resistances, rather than Solids. It would affect the mesh a little as there would be a boundary layer, but other than that the mesh should be similar - although they do require that a finer mesh is assigned to them.

[Royce_adsk]

I would suggest that you checkout the Permeability resistance type instead of the free area ratio.  That might make more sense for you model setup.

-Royce