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

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-μm 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 (D32) slightly varied with increased axial locations in the turbulent region. In comparison, D32 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 (Δ) value sharply decreases for the converging atomizer with the axial location in the turbulent region. In comparison, the RSF (Δ) value remains in a narrow range ( ~ 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 (Δ) displayed a similar trend except for the aerodynamic region with slight variation for the CD atomizer case.