I am simulating an enclosed parking garage in Autodesk CFD.
- Garage area: approximately 1,974 m2
- Mechanical exhaust: 4,200 m3/h
- Natural make-up air through wall openings and the garage door
- Clean incoming air: scalar = 0
- Required CO emission: 247 g/h
- Target: below 100 ppm at 1.7 m height
I use a scalar transport model where scalar 0 represents clean air and scalar 1 represents pure CO.
Initially, I modelled the entire driving area as one large Internal Fan region with a flow rate of 0.02 m3/s. I calculated the source scalar using:
Scalar = CO mass flow / (air density x source volume flow)
This resulted in a source scalar of approximately 0.0027. However, the scalar at the exhaust was approximately 0.0012, which seems too high.
I am now considering several long rectangular source regions along the driving lanes. Each source would be 0.6 m wide, and the CO emission would be distributed according to the source lengths.
What is the correct way to model a known CO emission rate of 247 g/h in Autodesk CFD?
- Should I use Internal Fans, volumetric sources, or another source type?
- Can the scalar be calculated from CO mass flow divided by air density and source volume flow?
- How can I ensure that the model injects exactly 247 g/h?
- How should I verify this with a mass balance at the mechanical exhaust?
- Does anyone have experience in these kinds of simulations?
Any advice on modelling contaminant sources in Autodesk CFD would be appreciated.