I have a model converted from
 

I have a model converted from STAR-CCM+, both as polyhedral and tetrahedral models, these models include an internal interface, which is troublesome to remove.

However, once the interface has been removed I can run the model in icoFoam and turbFoam without trouble. In simpleFoam as an MRF simulation the model never works. Every time I run MRF the model, omega explodes towards infinity. Once omega exceeds 1E+7, k quickly follows omega off to infinity as well.

I have tried using k epsilon and k omega turbulence. I have tried reversing the velocity at inlet and revesing the direction of rotation in the model. The result is always the same. four or five iterations is all it takes to explode and crash. Changing the timestep does not change the number of iterations to failure either.