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엔트로피 해석과 PIV를 이용한 직접 분사식 가솔린의 분무 특성에 관한 연구
우영완,이창희,이기형,이창식,Woo, Young-Wan,Lee, Chang-Hee,Lee, Ki-Hyung,Lee, Chang-Sik 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.7
To improve the fuel consumption and exhaust emission for gasoline engines, GDI(Gasoline Direct Injection) system was spotlighted to solve above requirements. Thus, many researchers have been studied to investigate the spray characteristics and the mixture formation of GDI injector. In this study, we tried to study the spray characteristics of a gasoline direct injector by using entropy analysis and PlV methods. The entropy analysis is based on the concept of statistical entropy, and it identifies the degree of homogeneity in the fuel concentration. The PlV method was adopted to determine the fluid dynamics information at the spray. From the applied results on a direct injection gasoline spray, we could find that the direct diffusion phenomena was a dominant factor in the formation of a homogeneous mixture at downstream of GDI spray especially under vaporizing ambient conditions, and mixing phenomena was also progressed by momentum exchange with induced air. In addition, the correlation between entropy and vorticity strength enabled to find their relation.
이색 PIV 기술을 이용한 5밸브 가솔린엔진 연소실 내의 유동특성 분석
이기형,우영완,박상찬,이창식,Lee, Gi-Hyeong,U, Yeong-Wan,Park, Sang-Chan,Lee, Chang-Sik 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.2
A 5-valve(intake 3-valve) engine has been developed to increase engine performance. These engines have a high power caused by the decrease of inertia mass of an intake valve and the increase of intake effective area. In this study, in-cylinder flow patterns were visualized with laser sheet method and velocity profiles at near intake valves were inspected by using a two-color PIV. In addition, steady flow tests were performed to quantify tumble ratio of flow-fields generated by a tumble control valve(TCV). Experimental results of steady flow test show that the cure of tumble ratio in intake 3-valve engine farmed as a S shape with valve lift changes. This tendency is different from the one in intake 2-valve engine. Using laser sheet method and two color PIV method, we can find that the intake flow through upper valve increases and the velocity gradient also slightly increases as valve lift increases. From this study, the in-cylinder flow characteristics around intake valves were made clearly.