BIMODAL DROP SIZE DISTRIBUTION BEHAVIOR IN PLAIN-JET AIRBLAST ATOMIZER SPRAYS

A plain-jet external-mixing, airblast atomizer has been studied. A bim odal drop size distribution behavior has been observed, where two diff erent drop size populations have been identified. It was observed that as a result of the impingement of the air stream on the liquid jet, a portion of the liquid flows back toward the orifice, arrives at the o rifice surface, spreads outward as a thin film in the radial direction , and is then atomized by the air stream emerging from the annular slo t. While the large-drop population is generated by the atomization pro cess occurring at the liquid-air collision region, the small-drop popu lation Is generated by the backflow mechanism. This phenomenon has bee n studied experimentally and an approximate analysis has been proposed to describe it.