Learning Forum

[sgillan]

Hi, I am trying to simulate a model in Ansys AEDT Icepak that has an enclosed cylinder. The cylinder is filled with dielectric oil, and I am using 2 heaters to heat the oil. There is no vent around the cylinder wall. Moreover, I have modeled a fan inside the cylinder to simulate the oil flow in the cylinder. I've attached the figure of my model.

I am running a steady-state solution-type simulation. However, the solution results are not consistent as I change the meshing. The results of the temperature of the oil and heaters change significantly as I change the meshing of the same model. 

However, when I run the transient solution type simulation with different meshes, I get the same temperature of the models for the given transient time (I ran it for 1 hr transient time). 

I want to know if steady-state simulation works well when there is no forced cooling or if there is no vent modeled, as I only have the natural convection for the heat transfer.

What can I look for for any potential problems in my model by considering the above observations? 

 

Appreciate your response.

 

 

[Rabindra Paul]

Hi Sgillan,  Thanks for asking question in the forum. I am assuming you are getting fully converged solutions both for steady state and transient runs. If there is a converged steady state solution then results should be independent of mesh. However, some problems could be inherently transient. You can run for more iterations (good mesh quality and recommended mesh resolution) to find out whether the results keep changing, which will indicate the problem is inherently transient. As it is a closed domain problem there is chance that no true steady state solution for this case. But results should not change with mesh, in my opinion.

I hope you are using correct heat transfer boundary condition for the domain. As the domain is closed the problem is challenging and will require good mesh and appropraite turbulence model. 

In any case, to investigate the problems and for better suggestion, it would be better to create support case so an available engineer can help.

 

Please let us know any comments.