Discussion Forum

I don´t exactly know what you want to model, but i watched your model and have an advice. At first not about computational time but about your boundary conditions. If you model it like this with the fixed temperatures for boundaries youu have some dirichlet boundary conditions, meaning they won´t change. So according to your temperature gradient and thermal conductivity they will act like a heat source if you lower the temperature of the big block. The same is true for your water to clay boundary. I don´t know if this is wanted but just wanted to mention it.

In General Phase change Problems with the comsol function need a sufficient small time stepping and fine mesh for correct solution. The spatial temperature difference and the difference from one time step to the other shouldn´t be higher than your transition Intervall between Phase 1 to Phase 2. So if you want to improve computational time get sure about your dimensions of temperature Gradient and take sufficient high time steps.