The influence of spill-line geometry on a spray generated by a pressure-swirl atomizer

Abstract

Abstract. An experimental investigation of characteristics of spray generated by a pressure-swirl atomizer (spill-return type) was performed using shadowgraphy and Phase-Doppler Anemometry (PDA). Several different geometries of the spill-return orifice were tested in terms of a spray stability and quality on a cold test bench. PDA measurement yields a drop-size distribution and velocity data while the shadowgraphy unveils a break-up process in detail. Performed measurements reveal significant differences in spray characteristics as well as differences in spray stability. The results suggest that the air core, formed inside the swirl chamber, passes through the spill orifice, which causes instability of the inner flow. These instabilities lead to a chaotic state of sheet breakup resulting in shortening of breakup distance. Obtained findings are used to propose possible changes in the atomizer design for improvement of its performance.

Influence of operating conditions and atomizer design on circumferential liquid distribution from small pressure-swirl atomizer

“…However, SA shows the most uniform spray pattern. This atomizer, the only one in this study, has a visually unstable spray in the same way as it was described in [3]. Because of the long-time measurement compared to the spray fluctuating frequency (which was about 5 Hz), data from the patternator are time-averaged and the spray may be not so symmetrical in the short time observation.…”