Need a macro to compute Diffusion at Inlets
 

Folks,

In the segregated solver in FLUENT, the net transport of species at inlets consists of both the convection and diffusion components. (For the coupled solvers, only the convection component is included.) The convection component is fixed by the inlet species concentration specified by you. The diffusion component, however, depends on the gradient of the computed species concentration field. Thus the diffusion component (and therefore the net inlet mass transport) is not specified a priori. In my Postproccessing UDF (EXECUTE-ON-DEMAND), I want to compute the net inlet mass flow (convection + diffusion) of a certain species. The product of F_FLUX(f,t) * F_YI(f,t,i) at that inlet boundary only computes the convective mass transport of that species. How can I access the diffusive component of that species ?

Thanks, Sridhar.