THE PERFORMANCES OF SWIRL JET ATOMIZERS AT VERY HIGH LIQUID PRESSURE

High pressure swirl atomizers have been investigated experimentally. Their sprays, confined in tubes, are used as air pumps for dust removal and methane dilution in mining and tunneling. An empirical approach is used to derive an optimum atomizer goemetry for improved air-mover pumping using liquid flow rate, drop size, spray angle and entrainment ratio data. A specially constructed patternometer shows spray maldistributions from atomizers machined to high tolerances. Phase Doppler and Malvern drop size data are in good agreement and show the drop size/velocity correlations are not strong at the point of measurement. Comparisons are made with previous approaches to correlating swirl jet performance which are based on classical free-vortex theory. Some broad agreement for Cd, drop diameter and spray angle is found although published equations overestimate the measured drop size. A modified atomizer parameter of the form K(D_s/D₀)¹⁻ⁿ as given by Dombrowski and Hasson, best correlates measured Cd and 2θ when using 0.2≤n≤0.3. This and other observations indicate the existence of turbulent flow inside the high velocity atomizer flows.