Influence of droplet spacing on drag coefficient in nonevaporating, monodisperse streams

Abstract

It is well established that droplet interactions profoundly influence the ignition and combustion behavior of droplet clouds and fuel sprays. Four-group combustion modes of a droplet cloud have been identified, with that of single-droplet combustion possibly being applicable in practice to only a very limited number of special situations. Such a special situation, however, can arise during the incineration of liquid hazardous wastes, where droplets with large diameters congregate at the outer edge of fuel-spray cones. One or more of these stray droplets then may individually pass through, or bypass, the main flame zone and lead to a failure mode in the incinerator. In this document, the influence of droplet spacing on the drag coefficient of individual drops injected into a quiescent environment has been determined through measurement of trajectories of single, monodisperse, nonevaporating droplet streams.