The Influence of Atomizing Gas Molecular Weight on Low Mass Flowrate Effervescent Atomizer Performance

Abstract

The relationship between atomizing gas molecular weight and spray mean drop size, Rosin-Rammler distribution parameter, and number averaged drop velocity is reported for a low mass flowrate effervescent atomizer-produced spray. Experimental data at lower gas-liquid ratios (GLR’s) demonstrate that an increase in the molecular weight of the atomizing gas increases mean drop size and decreases number averaged drop velocity. The increase in mean drop size is attributed to an increase in the thickness of the liquid annulus at the nozzle exit and a subsequent increase in the diameter of ligaments formed there. The decrease in number averaged velocity results from a decrease in jet momentum rate. A model developed to explain the atomization process indicates that the gas flow is choked at higher GLR’s.