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