# scalar density

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 May 28, 2008, 03:13 scalar density #1 James Guest   Posts: n/a 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

 May 28, 2008, 03:33 Re: scalar density #2 Polly Eda Guest   Posts: n/a do you want the density of your spray droplets or of the evaporated octane?

 May 28, 2008, 03:37 Re: scalar density #3 James Guest   Posts: n/a I want the density of the vapour (Octane vapour)

 May 28, 2008, 11:01 Re: scalar density #4 Pauli Guest   Posts: n/a 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.

 May 28, 2008, 12:31 Re: scalar density #5 james Guest   Posts: n/a 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

 May 28, 2008, 13:14 Re: scalar density #6 Pauli Guest   Posts: n/a 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.

 May 28, 2008, 14:24 Re: scalar density #7 james Guest   Posts: n/a Thank you Pauli. I got it. Thanks a lot.

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