I'm trying to determine how long it will take to heat up a flat plate (roughly 10mm thick, 1/2 meter by 1 meter) to 150°C slowly by convection and need help with the flow simulation setup.

The model is a simple insulated box with the plate floating in the middle (I'll add some kind of support later) and heated air blowing in from one side, out the opposite side.

I ran it as an internal time-dependent analysis, but after half an hour of computational time, I got about .3 seconds of real time (I'm anticipating about an hour of total real time, so this isn't acceptable).  Is there a way to streamline the computation?

Also, will the solver stop when it reaches steady-state?  How do I know the final amount of real-time it took to reach steady-state (can this be accomplished with a goal)?

This is my first attempt at time-dependent analysis, so any advice would be greatly appreciated.