Fluent species transport

SarveshinfernoSarveshinferno Member Posts: 2
edited February 19 in Fluids

I am currently trying to add source term to species transport equation and Continuity equation. My mixture contains air and water vapour. I am actually adding mass into the system(source term) but after I run simulation for few seconds I always see the total mass of the system is reducing. Btw my system is a completely closed 2d rectangle. Someone please help me solve this issue


  • sdebsdeb Forum Coordinator Posts: 153


    Since you have only 2 species, add the source term for the first species and the continuity equations.

    For example if water vapor is your 1st species and you want to add say 0.1 kg/m3 of water vapor in the domain, then add 0.1 kg/m3 to both water vapor species and the continuity [mass source]. Fluent will automatically add 0 kg/m3 [0.1-0.1] for the last species which is air.

    If you have expressions for the source term, then check if they stay positive through out. You can store them in UDM and then plot them to check.

    If the sign becomes negative for some reason, then it will behave as a sink.

    I hope this helps.



  • SarveshinfernoSarveshinferno Member Posts: 2


    Thank you so much for your reply, I sorted out that problem. My domain is actually a porous medium (with air and water vapor mixture) and I want to know how to model diffusivity terms in species transport equation for water vapor flow through the porous medium. Please help me.

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