Fluids

Why mass fraction become sinking, when I input source term in positive sign?

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• SEANGHAI
Subscriber

Hello! I have a question related to Fluent, I have input source term water vapor at the Inlet 2(positive sign), and I add some mass fraction of water vapor at the Inlet 1. Then the results of mass fraction of water vapor over the Inlet 2 should be increasing, but in contrast, it is decreasing, why? When I look to the concentration of water vapor, it looks OKay, because over the Inlet 2, the concentration keep increasing like what we expected. But how about the mass fraction of the water vapor is decreasing like a sink? Note that: I apply velocity 0.5 m/s at the inlet 1 and also the mass fraction of air and water vapor. At the Inlet2, I apply source term of water vapor. You can see my geometry and size including the name of each boundary as the following:

• SEANGHAI
Subscriber
Hello! Everyone! I knew my problem! the mass fraction at the Inlet 2 is zero, it is because I apply mass fraction= 0 to the surface of boundary Inlet 2. So now I am going to use zero diffusivity flux in stead of mass fraction.n