Learning Forum

[ll00023]

I used the Bilger's definition of mixture fraction to predict the coal combustion. 

the volatile formula of PRB coal is C1.16H3.4O0.71N0.0741.

Since char combustion is a secondary factor to determine the coal flame, I only consider volatile flame here.

volatile contains nitrogen element, which doesn't affect the oxygen consumption; by referring Haifeng Wang 2023 's work, in the coupling function, nitrogen item could be eliminated.

so I can use eqn.  8.4-9 and 8.4-10.

the mixture fraction result is not showing Boundedness [0,1], Monotonicity.  But stoichiometry preservation (0.146) is close to the flame location.

I assume this is due to the volatile release process. when using Eqn. 8.4-9, b_fuel - b_o = 2*Yc/Mc +0.5Yh/Mh+Yo/Mo, in which Yc = 0.148, Yh= 0.0361 from volatile , Yo=0.23 from oxidizer.

while for b, Yc is from the volatile in that cell, which is dependent upon the release process. I didn't find any solution for coal combustion.

how to make it right for coal combustion?

Thank you.

 

 

 

[Ren]

Are you wanting to model coal combustion using Fluent? Which combusiton model are you considering? Why do you need to construct the Bilger mixture fraction?