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Energy conservation in heat & mass transfer
Posted 27.02.2018, 11:15 GMT-5 Heat Transfer, Results & Visualization, Studies & Solvers Version 5.3a 0 Replies
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Hi !
I've currently work on a transicient 2D model with heat & mass transfer with a heat source drived by dilluted specie concentration (moisture in air flow).
In a 1st step I've validated the output results with experimental results. But, in a second step, when I want validate it with an energy conservation calculation (https://www.comsol.com/blogs/how-to-calculate-mass-conservation-and-energy-balance/), the results don't match.
I calculate the following global evaluation values: ht.dEi0Int, ht.ntefluxInt, ht.QInt. I arrange them to calculate the "error": ht.dEi0Int + ht.ntefluxInt - ht.QInt = error. And I divide this error to obtain an relative error: (ht.dEi0Int + ht.ntefluxInt - ht.QIn) / ht.QInt ; or (ht.dEi0Int + ht.ntefluxInt - ht.QIn) / ht.ntefluxInt .
I would like obtain an error bellow 1%. But even with the following options, my error is to hight: - strongly coupled solver with the calcul of the Jacobian matrix at every time step; - time step max = 1h (I simulate between 0 and 600h); - solver and Jacobian tolerence about 1e-4. Also my meshing is very tight and to increase the mesh number don't change the results.
Someone has an idea about ameliorations and options to abtain an error below 1%?
Thank you in advance :)
Alex
Hello Alexandre Malley
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