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setting initial temperature for a heat transfer and fluid flow module
Posted 1 ago 2023, 13:52 GMT-4 Fluid & Heat, Modeling Workflow, Physics Interfaces Version 6.1 1 Reply
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I am currently running a simulation on comsol where a lithium ion battery is cooled using a water cooled jacket where the jacket is made of aluminum. I used the lumped battery physics to model the battery and discharged it at 4C. I additionally used the heat transfer in solids and fluids physics as well as the laminal flow physics. I kept the ambient temperature and the batteries initial temperature at 313.15 kelvin and the water (coolant) temperature at the inlet of the jacket as 293.15 Kelvin. However after i ran a time dependent simulation for 900 seconds, the results gave me a strange plot. When I checked the battery temperature with respect to time, the graph started from a temperature of 293.15 kelvin, even though the batteries initial temperature was set to 313.15 kelvin. There is cooling however, the results would make sense if the battery temperature at time 0 was shown as 313.15 kelvin since that is what the initial condition was set to. How do i resolve this issue so as to get a temperature vs time graph which gives a temperature of 313.15 Kelvin at time 0
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Hello Mehwish,
It's hard to tell with much confidence without seeing your mph file, but it could be related to an inconsistency between initial values and boundary conditions. My first suggestion would be to make sure that you start your time-dependent solution step from the solution of a stationary step, or, if you want to only have one solution step, that you specify for the fluid temperature as a function of time that decreases from initially 313.15 to 293.15 over a short (but not infinitesimal) time. If the problem comes from something else, upload your .mph file (cleared of solution and mesh to keep the file size small) for better eduated ideas.
Best,
Jeff
-------------------Jeff Hiller