[Edwin_lee]

Hello guys !
Since my English skills are poor, I am writing using a translator. Please understand if there are any rude or slightly incorrect expressions.
I am asking this question because I would like to run a simulation to see how carbon monoxide spreads in an enclosed space. I want to simulate carbon monoxide being injected into the internal space through the inlet. If I set the internal space to air and the inlet part to CO and then set the volumetric flow rate in the boundary conditions, a message appears saying that separate settings are needed because the two fluids are different. How should I set the boundary conditions to simulate how carbon monoxide spreads into the internal space through the inlet? This is a situation where CO enters the internal space from the inlet at the bottom. uploading modeling photos together.

Thank you for reading my post !