source term in a gas mixture problem

Kevin

I am considering a gas mixture flow (A+B). I have set my problem as followings: bg fluid : A (density=ideal) active Scalar(01) : B

In my problem, gas B is being consumed at a rate of -10kg/m3s and gas A is also consumed at a rate of -30kg/m3s in a specific region.

To model this system, I have put the sorce terms as followings:

FLUXI = -40 in fluinj.f

S1P = -10 - FLUXI*SCALAR(01) in sorsca.f

However, I observed that the density of gas B ( =density*SCALAR(01) ) increases while I expect it would decrease due to the consumption.

So, I am puzzled now. What am I wrong with this problem? I'd like to get your valulable comments.

Thanks in advance.

Kevin