EFFECTS OF INJECTION PARAMETERS ON THE SPRAY CHARACTERISTICS OF SWIRL AND SLIT INJECTORS USING THE MIE-SCATTERING METHOD

Abstract

We investigated the effects of injection parameters such as injection pressure, ambient pressure, and ambient temperature on spray characteristics. We calculated the turbulence occurring point (tc), defined as the time required to generate a vortex, and the deceleration point (tb), defined as the time when spray penetration begins to decelerate, to elucidate the breakup mechanism of the test injectors. The spray velocity coefficient (Cv) was obtained to evaluate the spray characteristics. As the ambient pressure increases in the case of a slit injector, Cv decreases. We investigated the effects of nozzle tip shape according to injection pressure, ambient pressure, and fuel properties on spray characteristics and provide a Cv value of 0.38for the swirl injector with a spray angle of 60o and the slit injector under atmospheric conditions. The value of Cv in the case of a slit injector was reduced by increasing the ambient pressure. Our results suggest that Cv of a swirl injector is constant regardless of changes in ambient pressure, injection pressure, and fuel properties. On the other hand, Cv of a slit injector is altered by changes in ambient pressure.