pure melting of ice due to water at higher temp
 

I am trying to simulate pure melting of ice due to being in contact with water at higher temp. There is no flow of water. Both water and ice column are at rest. I am using all wall boundary condition at respective boundaries. I observed very rapid melting of ice at the interface and that too the melting was non uniform over the interface surface. In this case, I hope, the melting to be uniform. So I added interface boundary with wall and zero shear boundary condition. The melt rate is now very very low and it takes very very long time to give me any substantial melt rate. Kindly suggest some proper approach for the problem.

Thanks...