Forced Excitation of Swirl Injectors Using a Hydro-Mechanical Pulsator

Abstract

‡Experimental study of a swirl injector under varyin g pressure pulsations was investigated using a hydro-mechanical pulsator. The pulsator and the swirl injector were designed, built and cold flow tested at Two Phase F low Laboratory, at Purdue University. The injector was subjected to periodic pressure pul sation, up to 700 Hz, by the pulsator. The air core diameters inside the transparent vorte x chamber and the nozzle, as well as the spray near the exit nozzle were captured using the high speed camera. Periodic pressure oscillation across the injector changed the air cor e diameter as much as 15 %. Of importance is also the expanding and contracting spray cone angle which was changing by 6%. In addition, images of a propagating wave inside the vortex chamber and the nozzle during cavitation, which generated a non-uniform pulse wave of large amplitude and high frequency, were captured and are described qualitatively.