Electrolyte heat transfer problem
 

I have electrolysis process, with two concentric cylindrical electrodes. There is an electrolyte between the two electrodes. First, I just model heat distributing in the electrolyte, with heat generating in the electrolyte. In this case the heat leaves electrolyte on the two electrodes (after their free air surfaces) and the electrolyte free air surface. The CFX creates appropriate domain interfaces. For load(source) I've made a subdomain inner the electrolyte with Energy sources (Total source - it is in watts).The result heat distributing is almost good (symmetric in a main plane), but it has a "little bit" asymmetric. I think that maybe the mesh is wrong, or not enough fine. I refined it,but the result's characteristic didnt change. I gave opening boundary with static pressure on the electrolyte free air surface, and the outer electrode's outer wall is adiabatic for simplicity. Thus only the electrolyte free air surface can transfer the heat. What can be the problem with the non-symmetric heat distributing? (axis symmetric geometry, and axis symmetric loads and boundary conditions)

Regards