I am trying to complete a thermal study on a "heat exchanger". The results I am getting do not seem right but am unsure of what I am doing wrong in this study.
Looking at the attached photo, I have a contact set between the center pipe at coil with 0 thermal resistance. The steel center pipe is set at 600ºF. There is a convection condition set on the outside of the copper coil of 60 BTU/(s*in^2*ºF) with an ambient temp of 90ºF. What I dont understand is why the temperature of the coil drops almost instantly to the ambient temperature when it is no longer in contact with the main pipe.