Experimental and computational investigation of supersonic impinging jets

Neutralization of Bacterial Aerosols by Aerodynamic Shocks in a Novel Impactor System: An Integrated Computational and Experimental Study

“…Therefore, the study will focus on the centerline properties of the complex flow field that develops in the experimental impactor of Correspondingly the static temperature and pressure decrease as the gas expands. In is similar to the ones observed in experimental shadowgraphs and wave diagrams in the literature [2,29].…”

“…The generated impinging flow on a plate from a converging nozzle operating under sonic conditions results in the creation of a standoff shock whose properties can be changed by varying impactor geometry (distance between nozzle and plate x and diameter of nozzle d) and operating conditions [2,13,14,29,42,51]. In traditional impactors [21,22], the aerosol is collected by impaction on a flat surface.…”

“…Stewart et al (1995) [53] showed that bacteria collected by impaction are injured [53]; therefore, assessing damage induced by the standoff shock is impossible using current impactor designs. To avoid loss of viability by impaction, the flat surface of the developed impactor system has an opening (see (2) and (3) a flat surface with a 0.5 mm or 1 mm hole combined with a screw that accommodates the collection substrate make up the deceleration tube (these parts can be replaced with a Pitot tube to measure the stagnation pressure), (4) spacers allow variation of the plate to nozzle distance from 0 mm to 2 mm, (5) support holding the deceleration tube and flat surface at fixed distance from the nozzle, (6) exit chamber, and (7) Pitot tube which can replace parts 2 and 3 for stagnation pressure measurements. parts 2 and 3).…”

“…(1) Converging nozzle with an exit diameter of either 0.5 mm or 1 mm, (2) and (3) a fiat surface with a 0.5 mm or 1 mm hole combined with a screw that accommodates the collection substrate make up the deceleration tube (these parts can be replaced with a Pitot tube to measure the stagnation pressure), (4) spacers allow variation of the plate to nozzle distance from 0 mm to 2 mm, (5) support holding the deceleration tube and fiat surface at fixed distance from the nozzle, (6) exit chamber, and (7) Pitot tube which can replace parts 2 and 3 for stagnation pressure measurements. 10 2.2 Experimental Mach number before the shock (Mi) calculated using Eq.…”

“…Subsequently, three grid adaptation steps are applied to refine the mesh in areas with high pressure gradients, specifically in the area between the nozzle exit and the deceleration tube inlet. Li et al [34,37,35,36] Theoretical and experimental observations indicate the presence of instabilities in the flow structure of the impinging jets in the presence of an impaction plate [2,29,42].…”