Novel Laser-Based Technique for Measurements of Primary Atomization Characteristics of Liquid Jets.

摘要

The purpose of the research documented herein is to provide guidelines for the application of a novel optical technique, developed uniquely at Imperial College, London, UK, for measurements of primary atomization characteristics of liquid jets in different atomiser geometries. The novel technique measures the optical connectivity of a liquid jet leaving an atomiser by doping the liquid with a fluorescent dye (or using the natural fluorescence of the liquid) and illuminating the liquid body through the injector nozzle by a laser beam at a suitable wavelength. The liquid jet acts as an optical guide, which is interrupted when it breaks up, and, therefore, detection of the spatial, instantaneous fluorescent intensity distribution determines the distribution of the volume of liquid upstream of the breakup position, together with instantaneous intact length of the liquid jet. In addition, the surface wave instabilities along the air-liquid interface and the three dimensional structure of the liquid jet can be identified. The special feature of the novel technique is that the laser light is piped through the liquid nozzle, which provides its unique advantage over other techniques, since it eliminates the interaction of the laser light with the dense droplet field surrounding the liquid core that limits other techniques.