Concentration of species
 

Hello!

I would like some clarification on how to control the concentration of a species being injected into a system. The species is just a pulse tracer injected at the inlet and the concentration is being monitored at the outlet vs time.

The way I do this is by first solving the steady state solution with the species transport equation turned off, then I turn off the flow and turbulence equations and turn on the species transport equation. I go to my boundary conditions and at the inlet set the mass fraction of the species to 1. I would run a few transient steps to inject the tracer, then go back and set the mass fraction of the species back to 0. Finally I would resume the calculation until all of the tracer exits the system.

The problem I'm facing here is that the concentrations that I'm seeing are very high ~2M(mol/L), where in the real world the concentrations used don't typically exceed 0.2M...