An experimental investigation of discharge coefficient and cavitation length in the elliptical nozzles

Abstract

Cavitation in the nozzle is known to have influence on the liquid jet. In order to investigate the influence of cavitation, the experiment was conducted with a set of elliptical nozzles of approximately same area of cross section but varying orifice aspect ratio. Each of nozzle made of acryl for visualization. The measurements obtained for the elliptical liquid jet were compared with circular liquid jet. The flow rate increased with the injection pressure, and discharge coefficient decreased with the injection pressure. Especially the change of flow rate and decrease of discharge coefficients were generated with onset of cavitation. The injection pressure to start cavitation was 1bar regardless of any nozzle. The cavitation length for circular nozzle is longer than for elliptical nozzles in the same injection pressure. The spray angle has widest at the elliptical nozzle when the cavitation number is 1. And the spray angle at the elliptical nozzle has wider than at the circular nozzle.