[Saku03]

Hello everyone, I'm simulating methane combustion in a furnace and I want mass flow rate of NOx (in g/s) at an outlet. I don't know how to report that.
Do I need to define a new function for that ?
Please help

Thank you

[voidcrow]

I managed to do something like that with an "on-demand" UDF, which I apply after the simulation converges. Here is an example.

DEFINE_ON_DEMAND(compute_flow_rates) {
    Domain *d = Get_Domain(1); 
    Thread *t; 
    face_t f; 

    t = Lookup_Thread(d, YOUR_OUTLET_FACE_INDEX);
   
    real mass_flow_species = 0.0; 
  
    begin_f_loop(f, t) {
        mass_flow_species += F_FLUX(f, t) * F_YI(f, t, YOUR_SPECIES_INDEX); 
    } end_f_loop(f, t)
    

    Message0("Flow rate (kg/s): %e\n", mass_flow_species); 
}

It loops over all face threads in the outlet and cumulatively sums the value of mass flow rate of the species you want. You need to replace "YOUR_OUTLET_FACE_INDEX" (with the index you find in outlet boundary conditions) and "YOUR_SPECIES_INDEX" (with the index of the species that you want).


There is probably a way to do this in the GUI but I am unaware of it.

[Saku03]

That is great.
Thanks for your help