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Strange behaviour for multiphase modelling with combustion

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Old   November 2, 2020, 06:21
Default Strange behaviour for multiphase modelling with combustion
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Horst van Gras
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Hi,
I'm trying to simulate a combustion of H2+O2->H2O with later condensation of water.
Here is my setup:
-real gas soave redlich kwong, critical O2 and H2
-Eddy dissipation model for chemical interaction
-turbulence k omega SST due to its dampening properties
Because of convergence issues I did the following steps:
1)First calculate without multiphase modelling
2)Interpolate all data in the multiphase modelling
3)Deactivate the Volume fraction equation for a first iteration to have the same results as in (1)
4a)Start with Mixture(with still deactivated Volume fraction) multiphase model, always divergence
4b)Start with Eulerian (with still deactivated Volume fraction), not great but no divergence


Now my question: Why the more complex Eulerian model is converging? I thought the mixture multiphase modell is not as accurate but much more stable.
Which equations does the Volume fraction explicitly activate, I don't get it completely from the Theory Guide?


Thx for any help!
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combustion, eulerian model, mixture, multiphase, theory


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