ATOMIZATION CHARACTERISTICS OF AN ANNULAR SHEET WITH INNER AIR IN A SONIC TWIN-FLUID ATOMIZER

Abstract

This study examines the sonic twin-fluid atomizer based on gas-dynamic effects and atomization behavior with two distinct configurations: converging and converging-diverging (CD) atomizers. The atomization characteristics are compared by employing a 280-<i>&mu;</i>m annular liquid sheet with central core air. CD atomizer exhibited the sheet rupture breakup mechanism, whereas perforated wavy sheet disintegration was observed in the converging atomizer with both atomizers exhibiting a bursting phenomenon. Sauter mean diameter (<i>D</i>₃₂) slightly varied with increased axial locations in the turbulent region. In comparison, <i>D</i>₃₂ drastically increased with an increase in radial locations in the aerodynamic region, with more increment in the converging atomizer. Drop size distribution (DSD) showed unimodal distribution with a narrower range for CD atomizer in the turbulent region. In the aerodynamic region, DSD becomes more dispersed with an increase in radial location. The relative span factor (&#916;) value sharply decreases for the converging atomizer with the axial location in the turbulent region. In comparison, the RSF (&#916;) value remains in a narrow range ( &#126; 2-4) for both atomizers in the aerodynamic region. Sauter mean diameter (SMD), when plotted against the air-to-liquid mass ratio for the turbulent and aerodynamic region, exhibited a near-inverse relationship. The relative span factor (&#916;) displayed a similar trend except for the aerodynamic region with slight variation for the CD atomizer case.