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Volume or Weight ratio in modelling Air?

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Old   August 16, 2013, 09:40
Default Volume or Weight ratio in modelling Air?
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Ehsan
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in the constant folder I have set Air coefficients for JANAF thermoType from averaging air components.but have a doubt,I have set coefficients according to 75% N2 and 25% O2 as my adviser proposed,but I want to be more accurate,
is averaging based on weights more precise or based on volumes?
in what extent its important?is it necessary to change the approximate coefficients?
http://www.engineeringtoolbox.com/ai...ion-d_212.html
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Old   August 31, 2013, 12:32
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Hi Ehsan,

Do you mind providing more information? Namely how did you exactly define those values of 75% vs 25%?

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Old   August 31, 2013, 14:39
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Hi Bruno
I have multiplyed the JANAF coefficients(7 numbers) of nitrogen to .75 and for oxygen have multiplied them to .25 and then added them together,isn't it correct? the answers look fine but I want to know is this numbers accurate enough?
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Old   August 31, 2013, 14:50
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Hi Ehsan,

OK, still not enough information. So I ask in more detail:
  • How exactly did you do the math?
    • No need to specify all of the coefficient values, "a0, a1" and so on is enough.
  • And what results did you get?
  • And in comparison with the values used in the dictionary file, what values were you using before and are using now?
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