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Old   May 28, 2008, 03:13
Default scalar density
  #1
James
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Hi Experts, I am simulating gasoline spray in a GDI engine. Iso-Octane liquid is injected inside the cylinder during compression stroke. When I calculate the scalar quantity at TDC, I am getting the mass fraction of octane. I want the density of Octane at that time. Please help me

Thanks in advance

James
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Old   May 28, 2008, 03:33
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Polly Eda
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do you want the density of your spray droplets or of the evaporated octane?
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Old   May 28, 2008, 03:37
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James
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I want the density of the vapour (Octane vapour)
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Old   May 28, 2008, 11:01
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Pauli
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octane scalar mass fraction * cylinder mass is mass of octane. Divide by volume & you get density of octane. Am I missing something?

You should be able to do this in the post registers. That will give you a distribution. Or you can use the ecd file to get a cylinder average value.
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Old   May 28, 2008, 12:31
Default Re: scalar density
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james
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For getting the mass of the cylinder at TDC (in my case) is a problem.

i) Because at this point of time the cylinder mass is filled with both air and octane vapour. In other words each cell volume is filled with both air and gasoline vapour. Hence for getting the cylinder mass I need the densities( mass density) of both air and octane vapour.

Hence I need to find out both the densities of octane vapour and air residing in each cell at a particular time (say TDC). Also the densities depend upon temperature and pressure ( since moving piston Pressure increases). Please help me in this regard

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Old   May 28, 2008, 13:14
Default Re: scalar density
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Pauli
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StarCD reports the cell mixture density (getc dens). Multiply that density by the fuel vapor mass fraction (the vapor scalar value) & you have the fuel vapor density.

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Old   May 28, 2008, 14:24
Default Re: scalar density
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james
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Thank you Pauli. I got it. Thanks a lot.
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