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Species mass fraction

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Old   December 7, 2010, 23:57
Default Species mass fraction
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I am new user of Fluent and have one basic questions on using F_Y(c,t,i).

I solve a mass species equation for a aqueous mixture of N2 and O2, Now, I would like to calculate difference of their ionic concentration, I am wondering that if it is possible to use F_y(c,t,1)-F_y(c,t,0)?! How I can find out that what the i for O2 and N2 is?! For example, if i=1 denotes o2 or n2?!

If there is any easier way to calculate difference of ionic concentrations of O2 and N2 in the UDF?!

Thank you in advance!
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Old   December 10, 2010, 20:14
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The species are numbered according to their order in the Fluent panel (if O2 is first, i=0). Also, you probably want to use C_YI(c, t, 0) and C_YI(c,t,1). This will give you the cell concentration, not F_YI (f,t,i), which is the face concentration.

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