how is it possible: temperature higher than saturation temperature???
 

I am modeling a two phase flow (water and steam) and pressure is constant.
There s a heat source. Water evaporates at Tsat and steam phase is formed. Vol fraction increases. I see in the post processing that I get temperature higher than the sat temperature (super heated steam). I don't think this is correct, because the vol fraction of steam is nowhere 1. How is it possible that I find temp higher than sat temp even if vof steam < 1? Does the state-enthalpy in material has to do with that?
Please advice me!