you mean manually calculate the reference temperature, or manually calculate the htc, from heat flux and bulk temperature?
Also, I am still left with the question of what should i enter as my ref temperature, as that should be the input.
Or do you mean, that I don't observe htc and nusselt from surface-integrals as they are ref temperature dependent, just observe the converged heat flux (q), and manually calculate htc, form h = q/(Twall - Tbulk)?