Reply To: Particle count in a room

[Rob]

Breaking the question up. 

• If the HVAC flow is continuous and (more or less) constant flow it's probably steady state. Run and see what happens. 
• Particles can be run onto steady flow using transient, have a look at the options. You may want to review turning the flow equations off in the Solver Controls too. 
• If you don't need details it's best to remove them. If you need them, you need to resolve with the mesh. I always try and eliminate anything I don't need in a model as it'll speed up the solution and it's one less setting to think about.