Influence of design concept and liquid properties on fuel injector performance

An experimental investigation of the influence of design concept and liquid properties on fuel injector performance of airblast atomizers is carried out. Three injectors with distinctly different fuel filming concepts were employed in this program. In the experiments, the nozzle operating conditions (namely, air/liquid ratio and air pressure drop) and liquid properties were varied. Drop sizes were measured with a laser diffraction instrument and a photographic technique was employed for cone angle measurement. The results indicate that the method of spreading the liquid into a film has a significant effect on atomization quality. Also, surface tension has the most dominant effect on mean drop size. The drop size distribution data followed closely the modified Rosin-Rammler type under almost all conditions. Equations to correlate mean drop sizes to distribution parameters were derived to facilitate the prediction of the range of droplets in the spray.