air flow schematic Air flow in CFD chamber instrument. Air comes in at the top and out at the right. Inlet and exhaust flows are ~1 L min-1. Sheath flow is ~9 L min-1 and recirculates.
cut-away view Cut away view shows inlet impactor that removes particles > 2µm upstream of CFD chamber. Construction is based on compression tubing tee. Two such impactors are used.
Particle removal efficiency plot Efficiency of inlet impactor to remove particles. (Dots) Measured efficiency for ambient air, double impactor, 0.8 L min-1. (Thin line) Theoretical collection efficiency based on Ranz and Wong (1952) equations for a single round jet impactor with 0.8 L min-1 and particle density 1.5 g cm-3.