Hi all,
I am working on methanol steam reforming using packed bed for hydrogen generation. I am using FLUENT software for CFD simulation.
In reference paper, authors mentioned that effective mass diffusivity will be defined as:
D_eff= (porosity^tortousity)*Diffusion coefficient, which results in ~ 2.404 e-5
But, this is valid only for catalytic porous zone, for other zones where reaction is not taking place ie.. simple fluid flow region, this effective diffusivity will be defined as:
D_eff= Diffusion coefficient, which results in ~ 6.8 e-05
(As porosity for non-porous zone will be equal to 1).
I am trying to define it using UDF as mentioned by DEFINE_DIFFUSIVITY in FLUENT. But, I'm facing some issues in defining this, like THREAD_ID etc..
Please help me with this if there is any appropriate format of defining such UDF in FLUENT.
Alankrit Srivastava is your model an advection-diffusion-reaction model, then intraparticle pore diffusion will occur in the catalytic porous zone (pore diffusion coefficient) and/or pore surface diffusion on the solid catalyst surface (surface diffusion coefficient). To add porosity for the non-porous zone is it not correctly 0 instead of 1.
Further, the values for the effective mass diffusion coefficient and effective diffusion coefficients separately are to be specified in the diffusion flux terms for the species continuity equation (simple fluid flow domain) and species conservation equations for the fluid phase (catalytic porous domain) respectively
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