You can make a named selection (if you are using workbench). Just to easily identify the face.

Once the solution is done, you can go to the reports, then to surface integrals -> Area weighted average. Select field variable as wall fluxes and surface heat transfer coefficient. Select the face you want to see the result and press compute.

You can also write it to result file at every time step if you are running a transient simulation.

You can use this document .

Surface integrals -> Area weighted average. Select field variable as wall fluxes and heat flux (in case of const T), Then divide q/(Tsurface-Tfluid)

I agréé with Hardik and mohamed. Just be sure to well define the reference area . As your calculations are done

Thanks to all for your appreciated support.

Wow! The document provided by Lalmi Djemoui is already a nearly historic Fluent document, featuring Fluent 6.0 from 2008. But convective flows over heated plates have not so much changed since then... Interesting to see the user interface of that time, compared to what we are used to use nowadays.

hello,

like Thomas Frank, this historical document has raised much of old nice memories .......