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Hello Guys, I am new to COMSOL . I needed to include a "mass source" in Darcy law model and "heat source" in heat transfer in porous media model.The source term is as follows Mass source formula: -(1-porosity)*m
where, porosity=0.5, Kinetics Equation: m=Caexp(-Ea/(RuT))log(P/Peq)(rho_ss-rho_s) rho_ss=3240kg/m^3, rho_s=3200kg/m^3, Ca=100(1/s), Ru=8.314(J/kg.K), Ea=3e5(J/kg). Heat source formula: (1-porosity)dHm where, dH=30800 J/mol
Peq is found by van't Hoff equation, Peq=exp(A-B/T) where A and B are material constants, T is domain temperature and P is gas pressure. The problem that i have is (i) when i try to include "Peq" and "m" formulae in global definitions>variables, i get error message in exp and log functions. when i remove exp and log functions from the respective equations, no error message is displayed. I don't know what to do. Is it because P and T (the unknowns) should be given some arbitrary value initially or should i do something else? Your suggestions will be greatly helpful.Thank you.