Ansys Employee

Thanks, what are the three phases? 

The problem is with the model stability. Basically, the solver is unstable because of something, that's caused the stabilisation routines to be used and they've eventually failed. If cp=0 because of a temperature dependent property that needs checking, but equally that's only reported after the temperature field has hit 1K. 

Check the mesh quality (cell quality and mesh resolution etc). If that's OK try running single phase. Then multiphase and so on.