How to display the mass fraction of gas components？

MFiX
#1

Hello，developers！
Why are the options for these gas components grayed out and unchecked after the chemical reaction is added?What do I have to do to output the gas mass fraction？
Here’s my arithmetic file, looking forward to any possible answers, thanks!

d4aa41fa121792a7c81dc285a13e87b
d4aa41fa121792a7c81dc285a13e87b1745×866 103 KB

combustionCase(1).mfx (21.3 KB)

#2

This is because you have turned off species equations for the gas phase. Go to the Fluid pane and turn the species equations on.