Considering laminar flow under constant heat flux boundary condition, we can find the average heat transfer coefficient as follows:
Average heat transfer coefficient = (Heat flux)/(Tw-Tref)
where, Tw=Average wall temperature
and Tref=Reference or bulk mean temperature.
How to estimate Tref using FLUENT?
Thanks in advance
with regards
You have already the Tw as an average value. You have also the Tref distribution given by Fluent. Based upon this result you can ask Fluent from the "Report" to give you an average value of the Tref over the whole mass of the fluid. You can use that value. Normally Fluent has multiple options for the average value. You can take that one it fits you.
Dear Nilesh
you need to draw a line at the wall and a line on the center
calculate the T in both lines and you can get the h avg from the equation you provided above
Regards
Dear Nilesh
If you would like to use the bulk temperature in the heat transfer coefficient formulation, you may use (temperature*velocity)/(velocity) with Costum Field Functions in Define tab. Then, the provided bulk temperature should be reported by the surface integrals in the Results.
Regards.
Dear Nilesh:
You can plot or tabulate from Fluent the local heat transfer coefficient h(x) for example in the direction of flow, then numerically integrate these values to get the average heat transfer coefficient. For Tref in your equation, this is the bulk mean temperature of the fluid that is could be the arithmetic mean between inlet and exit.
Tref can be modified by you in the list of reference values. Instead, you can determine an average temperature of your system and externally evaluate (outside the fluent environment) the heat transfer coefficient
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