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scalar expression error

Posted Jan 17, 2010, 8:49 a.m. EST 0 Replies

Peter Firstian
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Hi everyone, right now i'm working on COMSOL 3D (conduction and diffusion; conduction and convection). I'm very confuse about what is happening on my model which I input them on scalar expression. the expression is like this:
KA = 37.476[1/Pa]
KP = 143.99[Pa]
E = 19.3[kJ/mol]
A = 16614[mol/(m^2*s)]
ks2 = A*exp(-E/(8.314[J/(mol*K)]*T))
P_ch4 = c_ch4*8.314[J/(mol*K)]*T
P_h2 = c_h2*8.314[J/(mol*K)]*T
rate = (ks2*KA/KP)*(((KP*P_ch4)-(P_h2^2))/((1+KA*P_ch4)^2))



The dependence variable are c_ch4, c_h2 and T which the initial value are 18000, 0, and 300



I need to modify the reaction rate due to its produce too little hydrogen, so I modify the A, KA and KP. Unfortunately, nothing is happened. I don't know why but its results as the same even if I change the A, KA, and KP in extreme. Ihope somebody can help me solving my problem. I really appreciate it.





Regards,



Peter
0 Replies Last Post Jan 17, 2010, 8:49 a.m. EST
COMSOL Moderator

Hello Peter Firstian

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