# Derivation of formulas for the viewfactor method and additional questions

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July 24, 2022, 13:59
Derivation of formulas for the viewfactor method and additional questions
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mo
Join Date: May 2022
Posts: 24
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Hello everyone.First time asking a question.First, I apologize for raising the same question on another forum.

I am currently studying the ViewFactor method, one of OpenFOAM's radiation models.The ViewFactor model solves the following equation:

Quote:
 View factor radiation model. The system solved is: C q = b where: Cij = deltaij/Ej - (1/Ej - 1)Fij q = heat flux b = A eb - Ho and: eb = sigma*T^4 Ej = emissivity Aij = deltaij - Fij Fij = view factor matrix
1 However, I am not sure how this equation is derived. What is the process by which this formula was derived? Am I correct in assuming that q is the net heat flux emitted at a given surface?

2 In the ViewFactor method, in addition to the variable q, there is another variable qr. I do not know the difference between q and qr.What is the difference between q and qr?

3. I understand that the qr obtained is incorporated into the temperature boundary condition, but I do not understand how it is incorporated. how is qr used in determining the temperature?

I know this is a poor question, but I would appreciate if someone could enlighten me!

viewFactor.C

viewFactor.H