Hello,
I am trying to simulate a simple heat exchanger which has a laminar flow of water inside the single slab channel and a phase change material stored underneath. The heat exchanger has one row of fins on the slab with air between the fins. The photo of the heat exchanger is attached.
While I run the transient simulation, the time steps of the transient solver are extremely low resulting in a very long runtime. As seen in the convergence graph, the Reciprocal of Time Step Sizes are extremely high and after 175 time steps, the simulation has reached only 0.0711 seconds. The simulation was running for over a day. This is while a simple heat transfer simulation without adopting the phase change material is not so time-consuming.
Is there any way to improve the timing or is COMSOl generally so slow on phase change material modeling?
Mahdi,
From the image you uploaded, I can see that the dimension of the fins are in the order of 40 meters. Is that correct?
It depends on a lot of factors:
- type of geometry, here you have a 3D geometry
- type of physics, here you have many complex physics interacting (e.g. phase change, laminar/turbulent flow, heat transfer, etc.)
- type of mesh, which mesh did you use, structured? Unstructured?
Prior to have such complex simulations, proceed by one step at a time, starting from simple geometry, adding one physics at a time, checking the solution with analytical ones (when available), check the grid independence of the results, and so on.
Regards
Hello,
To clearly help you, we would need more details about your PCM model.
Are you trying to involve natural convection or just doing a conduction only simulation because if you are only going for a conduction only simulation it should not increase the simulation time that much.
Moreover, what are your boundary conditions and are you trying to simulate the melting process or solidification process or both and how these boundary conditions and initial are setup in COMSOL.
If you can provide these details i believe it would make it easier for us to help you identify the problem.
Best regards,
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