[hiddenbunny]

Hi there,

The questions is related to replicating a constant injection tracer test for an indoor environment. The experiment involved injecting a tracer gas with a known constant flow rate next to a window, while the air coming into the space has variable flow rate.

I have tried to do this using multi-compnent flow in Star CCM+ but the only setting allowed at the opening boundary is either mass or molar fraction. Since the tracer gas is injected at a constant rate but the the flow rate through the opening boundary is not constant, neither method will work. I thought about writing a user function automatically adjust the fraction as the flow rate changes, but I don't see an option to link the input to any functions.

I have also tried to see whether I can write a user field function to describe this by isolating a small region near the window as the source. However, unlike what I can do with heatflux, species did not allow me to select a field function.

If anyone has a suggestion on how I might approach this different it will be greatly appreciated.

thank you.