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 christopher0 April 6, 2010 07:01

calculation of htc

hello,
I performs calculations in CFX. One of my aims is to determine the heat transfer coefficient based on two steps. First step performs calculations using adiabatic wall boundary condition allows no heat transfer across the wall boundary. In second step (after convergence) I use isothermal wall with Ti=Ta-dT. Ta -gas temperature at adiabatic walls; Ti -gas temperature at isothermal walls; dT -temperature difference, for example 150K. These calculations allow to get wall heat flux (q) and then the heat transfer coefficient can be determined from the formula: htc=q/dT. I have problem with finding information about this method. Can you give some references describing this method?

 dvolkind April 6, 2010 12:41

Hello!

I don't really get what You are trying to do with adiabatic wall boundary. Are You modelling both fluid and solid domains?
Anyway, to calculate HTC properly You need to apply temperature BC to the wall You are interested in. Then, in CFX-Post divide the average heat flux by [T(wall)-T(fluid)]. Heat flux is calculated via Function Calculator - > AreaAve (heat flux)@wall. The choice of T(fluid) depends on the problem.

 ztdep April 7, 2010 00:53

Dear friends:
Since the wall is adiabatic, that means the heat flux is zero.
am i right?

 dvolkind April 7, 2010 03:09

"Quote: Since the wall is adiabatic, that means the heat flux is zero.
am i right?"
Yes, You are right.

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