Pressure-swirl spray in a low-turbulence cross-flow

Abstract

Pressure-swirl atomisers (PSA) produce fine spray and are used in many industrial, chemical and agricultural applications of sprays in flowing environments. The study examines spray from a small low-PSA exposed to low-turbulence cross-flowing air. The PSA spray was investigated experimentally using phase Doppler anemometry (PDA) and high-speed visualisation (HSV). The atomiser sprayed water into cross-flowing air at varying flow velocities. The tests were provided at a newly developed wind tunnel facility in the Spray laboratory at Brno University of Technology. PDA results contain information on the size and velocity of individual droplets in multiple positions of the developed spray (after the liquid break up is completed). A high-speed camera (HSC) documented the complexity of the liquid discharge, the formation and break-up of the liquid film, and the spray morphology. The data is relevant to CFD engineers and scientists involved in modelling as they can highlight the crucial phenomena to be considered in numerical simulations of the disperse two-phase flow case. The case allows us to study 1) Liquid discharge and sheet formation, the primary break-up of the liquid sheet, 2) secondary break-up and spray formation and 3) the Interaction of the sprayed liquid with surrounding air: gas–liquid mixing, droplet collisions, droplet clustering and droplet reposition.

Figure 1a: Spray image form high-speed imaging
Figure 1b: Optical measurement using PDA (taken from [1])