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Pressure during compression gets too high

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Old   June 29, 2007, 07:38
Default Pressure during compression gets too high
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A Student
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Hi I am simulating a closed system. The pressure should rise from 30 to 4000bar by a piston compression. My problem is that with the initialized pressure of 30bar and the calculated volume to reach this pressure (though compressibility and displacement volume), the simulated pressure reaches the 400bar at around 50 and even rises further upto several 100000bar. Anybody has an advice for me?

Thanks
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Old   June 29, 2007, 13:24
Default Re: Pressure during compression gets too high
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Andrea
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Hi, you are contempling also the various heat transfer? I don't know what kind of fluid you're simulating but heat transfer can vary very much the kind of effective compression... May be if you tell more somebody can help you more than me! Bye
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Old   July 2, 2007, 02:26
Default Re: Pressure during compression gets too high
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Its a synthetic oil and the compressibility is in the user code just dependent on the pressure...
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Old   July 2, 2007, 02:31
Default Re: Pressure during compression gets too high
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Mike
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Hi..try using bulk modulus factor since it is oil, as liquids of such nature are subjected to compressibility.
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Old   July 2, 2007, 02:41
Default Re: Pressure during compression gets too high
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Thx for the qouick answer, but where can i set the "bulk modulus factor"
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Old   July 2, 2007, 07:28
Default Re: Pressure during compression gets too high
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I already set the bulk modulus factor in the densit.f user-file with the calculated data through the formula: K=-V*dp/dv , but still the pressure gets too high

Any idea why?
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