Hello,

I am modelling the temperature distribution over the wall-thickness of a rubber pipe based on the temperature of a fluid flowing inside the pipe. The conditions are as follows:

T_fluid = 100°C, T_environment = 22 °C

Based on tests, it was estimated that the temperature at the inner wall which is in contact with the fluid, is 108 72 °C after steady-state was reached. So :

T_inner wall = 72°C, T_outer wall = 62°C

My approach was to play around with the "Film Coefficients" in the convection boundary condition until I got the above mentioned inner and outer wall temperatures.

I was quite surprised to see that multiple combinations of film coefficients can produce the same temperature distribution within the solid:

My question : **what role (if any) does the film coefficient play in a thermal analysis? And what does it mean practically, when different sets of film coefficients produce the same results?**