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 Vamsee February 26, 2009 02:01

Porous Media UDF

Hello Friends,

I am Vamsee, doing my M.Tech at IIT Kharagpur.Presently I a doing my project on Metal Hydride Hydrogen compressors. For my project I need to simulate a metal hydride bed (packed porous bed) with heat transfer.I am facing problem while writing UDF for source term in the energy equation. I will explain my problem statement clearly so that anyone one could help me solving my problem.

The source term goes like this.

S= density*dH*N/(2*Mol wt)* (dx/dt)

where dH,N,density are all constants and doesn't depend on temperature.

x= hydrogen concentration

t = time dx/dt = 1000*A*(x-xf)/B* exp(-Ea/(R*T))

B = xi-xf xi= Initial concentration of hydrogen in metal hydride = fixed value xf-final hydrogen concentration in metal hydride = fixed value ( can be initialized before the problem) A= (Pb-Peq)/Peq Pb=constant Peq=(dH/(R*T)) +constant Ea= constant T=Temperature

I am unable to write UDF for the source term as I am finding difficulty with the hydrogen concentration term x Can I use UDS in this case?