Experimental Quantification of Flow in an Impactor

In this work, the flow field inside a trap impactor is experimentally and numerically investigated using PIV, backlit imaging, and COMSOL simulations. Trap impactors are a class of impactors used to separate particles based on size and are typically used in areas such as air quality monitor, biological sample filtering, and other applications. Using an Nd:YAG double pulsed laser for PIV, the axisymmetric flow field emanating from the impactor nozzle for Reynolds numbers between 2000 and 18000 are captured between the exit plate of the nozzle and the top of the trap. Velocity profiles in the axial and radial directions are plotted demonstrating jet development downstream of the nozzle exit and return flow impacting on the exit plane. Backlit imaging is used to capture large scale flow features, driven by viscous shear and turbulence, present in the flow.