Volume or Weight ratio in modelling Air?
 

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

Hi Ehsan,

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

Best regards,
Bruno

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?

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?

Best regards,
Bruno