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Modelling compressible diesel with cavitational effects

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Old   July 22, 2020, 08:35
Default Modelling compressible diesel with cavitational effects
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Maximilian Ringel
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Hello,
I have to modell the compressible flow in which Diesel is used. Effects like cavitation should be implemented as well. Today I started modelling the compressibilty of diesel (diesel-liquid). Instead of using constant density, I selected "compressible liquid" and changed the Reference Density and the Bulk Modulus. (One thing I wasn't sure about is the Density Exponent, typed in "1" for it, but I don't know what that means...)
After it, the calculation diverged after 4 Iterations. When using ideal gas, the calculation runs through, but with unrealistic density values (up to 1600 kg/m^3, instead of realistic 950 kg/m^3, which is normal because a gas can be compressed easier than a liquid and diesel is not a gas). I also tried to use the piecewise-linear function, but it is only possible to do this in terms of temperature.
Is there a way to model this supposedly simple context? The dependency between pressure and density in my case can be described with a linear function, maybe a UDF can help but I don't know how to write it...
Second thing is that it all has to work with cavitation, so later I'm going to use the Multiphase Mixture model, and for those cavitational effects the Zwart-Gerber-Belamri model will be used.
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compressible liquid, pressure and density, udf


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