Reply To: Use an output as input for the next timestep

[Sheldon Imaoka]

Thanks for your clarification.
If only your bulk temperature is a function of time, in the Details view of your "Convection" object, you can change "Edit Data for: Ambient Temperature" and specify it to be a function of time. Then, you can switch "Edit Data for: Film Coefficient" and set it as a function of temperature. The "Coefficient Type: Surface Temperature" allows you to define that the temperature-dependency is based on the surface temperature. A perfect step function cannot be used since you need unique values for a given surface temperature, but you can then define film coefficient changing before and after Tsat.
If both your bulk temperature and film coefficient change as a function of time, then you will need to define the Convection loading via a "Commands (APDL)" object since film coefficient would be a function of both time and surface temperature. Section 3.5.16. "Applying Loads Using Tabular Input" and the Thermal Analysis Guide of the Mechanical APDL help documentation could be a starting point to understand how to define such loads in APDL.
Regards Sheldon