Hello i am doing a heat transfer analysis of fluid flowing through a sub-channel. Constant heat flux condition is given to the wall. Using Mass flow inlet and Pressure outlet.

In postprocessing of CFX there is a parameter "wall heat transfer coefficient". I want to know how is it being calculated in CFX. Actually i am calculating HTC by the following relation

q=h*(Ts-Tb) where,q=Heat flux, h=HTC, Ts=surface temp.,Tb=bulk temp. would u plz let me know about the parameter "wall HTC" and whether my way of calculating HTC is right? thank you.

Hi,

Yes, you calculation is correct - although if you are using radiation modelling you may need to use just the convective wall heat transfer.

The calculation of h in CFX is described int he manual in the section describing the turbulence model at the wall (assuming you are using a turbulence model!). In short, CFX calculates a wall heat transfer, then estimates an ambient temperature and calculates h based on that. It does not model h directly.

Glenn Horrocks

thanks glenn.