Hello Amine

In actual I've to solve the following equation, but there is not any direct provision for solving in terms of concentration.

" alt=""> where C = concentration, Source = -kb.C

But species transport module uses the following equation which uses massfraction and density rather than concentration. and the rest terms are same as of above equaiton.


So, I converted concentration into massfraction, as I already know the density of mixture and then gave the input values for simulation.


One another option:

Can I use "User Defined Scalar" for directly solving the 1st equation which contains concentration terms ?

As in my problem, the fluid domain is also porous. So, I also have to give porosity to the fluid domain.

If yes, can I give porosity for the flow domain in cell zone conditions for the equation to be solved by  "User Defined Scalar" ?

  • And also do I need to give the velocity which is represented by 'u' in the equation -  in the UDS code or in the boundary conditions ?

  • And also the term 'D'  which represents diffusivity, where can I define it - in the material properties or in the UDS code ?

Thanks and regards