Heta transfer coefficient

Danny Klein

Dear Fluent users. I seem to have a problem with the heat transfer coefficients calculated by Fluent. I've solved an impinging jet (conjugated) problem over a surface (uniform heat flux was imposed over the surface). I've asked for the area weighted average heat transfer coefficient (havg) and for the area weighted averaged temperature (Tavg), both for the same surface. In order to calculate the total heat flux I performed the simple calculation: qtot"=havg*(Tavg-Tref). Tref was pre defined. My expectations were to find the output equal to the heat flux imposed or the one calculated over the surface by Fluent (Area weighted average ->Wall Fluxes -> Total surface heat flux). Yet there was a mismatch of up to 8% depended on the case solved. My calculation were 3ddp and were converged for less than 10^-7 for all variables. Can someone explain my mistake or is it really a Fluent bug? Thank you in advance, Danny.