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I want to modify the equation in "surface-to-surface radiation"
Posted 13.07.2012, 05:33 GMT-4 Materials, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.2a 0 Replies
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I want to edit the "surface-to-surface radiation" equation in equation view.
In the weak expression, the equation is
"(ht.epsilon_rad*sigma_const*model.input.minput_temperature^4-ht.J0u+(1-ht.epsilon_rad)*ht.G_rad)*test(J)"
But I want to modify this equation.
I want it become "(A*sigma_const*model.input.minput_temperature^4-ht.J0u+(1-A-Tr)*ht.G_rad)*test(J)"
I set the parameter A & Tr in root->global definitions-> parameter A=0.12 Tr=0.8 .
but when i compute the model, I will see the COMSOL error
The error is here
Failed to evaluate variable.
- Variable: model.input.minput_temperature
- Geometry: 1
- Boundary: 67 68 69 70 71 87 96 99 127 144 147 153 172 173 174 175
Failed to evaluate expression.
- Expression: d(((A*sigma_const*model.input.minput_temperature^4-mod1.ht.J0u+(1-A-Tr)*mod1.ht.G_rad)*test(mod1.J))*(dvol),{test@87})
I think my modify equation is wrong , but I don't know how to fix it.
Plz somebody help me.
Hello Dong-Yi Wu
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