직접분사식 가솔린 엔진용 경사노즐 스월분무의 형태 결정 인자

Abstract

The swirl spray for direct injection gasoline engines was controlled using the tapered nozzles to fulfill the requirement of various combustion systems and the control mechanism causing the spray alterations were investigated. This study focused on how the correlation between taper angle, inclined angle of tapered nozzle, and flow angle affects the swirl spray shape. The macroscopic spray images were captured and velocity and droplet size distribution of tapered nozzle swirl spray were measured to understand the spray alterations at different taper angles. The result showed that fuel did not pass some area of nozzle exit and U or V shape spray was generated when the taper angle was higher than 90o minus flow angle. The velocity and fuel distribution of swirl spray were more asymmetrical and the spray robustness was enhanced when the taper angle was increased. The opened swirl spray, U or V shape spray generated when the taper angle is more than 90o minus flow angle, showed the possibility for the application of spray-guided combustion system as a result of enhanced spray momentum and reduced static air pressure drop inside the spray compared with the conventional swirl spray.