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Problems with ModelicaTest.Fluid.TestComponents.Vessels.TestSimpleTank #4526
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See PR #4527. If successful, will need to be back-ported to maint/v4.1.x |
@Esther-Devakirubai please back-port #4527 to maint/4.1.x, then we can close this. |
Esther-Devakirubai
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* Avoid the tank to ever become completely empty * Update Modelica/Fluid/Vessels.mo As discussed at the meeting * Update Modelica/Fluid/Vessels.mo Removed explicit reference to value in assert string Co-authored-by: Thomas Beutlich <[email protected]> --------- Co-authored-by: Hans Olsson <[email protected]> Co-authored-by: Thomas Beutlich <[email protected]>
casella
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…4545) * Avoid the tank to ever become completely empty * Update Modelica/Fluid/Vessels.mo As discussed at the meeting * Update Modelica/Fluid/Vessels.mo Removed explicit reference to value in assert string --------- Co-authored-by: Francesco Casella <[email protected]> Co-authored-by: Hans Olsson <[email protected]> Co-authored-by: Thomas Beutlich <[email protected]>
Successfully back-ported. There are still issues, but they are covered by #4548 |
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As reported here, ModelicaTest.Fluid.TestComponents.Vessels.TestSimpleTank is failing because the temperature of the fluid in the tank is getting out of range.
I investigated the issue in depth. The fundamental problem is that the base class
Modelica.Fluid.Interfaces.PartialLumpedVolume
is governed by a dynamic mass and energy balance, with a state variable change to more suitable state variables than mass and internal energy, in this case level and fluid temperature.It is clear that the energy balance equation becomes singular when the level (hence the mass) becomes zero. Don't even mention what happens when the mass becomes negative (anti-matter anyone?). Some solver could miraculously handle the singular case without producing utter garbage, but I don't think that the MSL should rely on miracles, it should only contain solid, well-posed models that can safely be handle by all MLS-compliant tools.
Bottom line: the tank should never get completely empty.
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