Very high unreal temperatures around the heater in the tank
 

Dear friends,

I am trying to simulate heat transfer inside a tank using electric heaters. Salt is stored in the tank with initial temperature of 300C and it is heated with 4 heaters for 8 hours. The salt temperature distribution after 8 hrs is of particular interest. The tank is cylindrical and I am only modeling 1/4th of the tank and assign periodic boundary conditions to the left and the right surfaces.Natural convection is also simulated.
I run the simulation for two minutes to check the temperature profiles inside the tank. Although the solution is converged according to the residual values, the temperature right around the heater is extreme and unreal. I tried to improve the mesh, but it didn’t help. I am not sure how I can fix this problem. I really appreciate if you could please help me in this regard. I attach here a picture of the simulation after two minutes.

Try to add an inflation layer on the surfaces emitting heat, and try to reduce the Energy equation under relaxation factor.
Hope that helps.

You can try converting your grid to polyhedra, it some times fixes this type of unreal temperatures. Also as mentioned above, reduce the URF for energy to 0.5