# A problem related to writing an expression for htc in CFX?

Hi,

My problem is that I want to write an expression for htc as follows:

htc= Wall Heat Flux/(Ts-Tf)

where Ts is solid temperature and Tf is fluid temperature and I already drew charts for solid and fluid temperatures along the axial direction. But when I use the above expression for htc, I get error. Is there anybody who knows how can I solve my problem? since Ts and Tf change along the axial direction and I couldn't use constant temperature.

Many thanks in advance

Hamda

## Comments

Dear Amine,

yes I need that for post processing.(in CFD post)

I assume the solid temperature belongs to another domain (solid). Create a line and then plot respectively the fluid temperature and solid temperature along that line. You need to use the option "All domains" when creating the line.

Dear Amine,

Thank you for your response.

I already created 2 lines named fluid line and solid line to plot solid and fluid temperatures . But with ONE line how can I plot Ts and Tf? since in "variable" we can just select "temperature" or "total temperature" and there is no other option.

Also I want to show Nusselt number distribution on a selected sphere. How can I do that? I should insert a volume(sphere volume)? and draw a contour of it?