GDI喷油器超高压乙醇喷雾的宏观特性
Spray Macroscopic Characteristics of GDI Injector Fueled with Ethanol Using Ultra-High Injection Pressure

为探究缸内直喷(GDI)喷油器乙醇燃料在超高喷射压力下的喷雾宏观特性, 运用纹影测试法和高速摄影技术对喷射压力为10～60 MPa的喷雾进行了测量, 系统研究了喷雾形态发展、贯穿距、锥角以及投影面积的变化规律．结果表明：提高喷射压力, 喷雾枝状结构出现时刻提前, 但超高压喷射下枝状结构形态界限变得模糊; 喷雾整体及其核心区贯穿距在喷雾前期较快增长, 进入喷雾中期后增速明显下降; 随着喷射压力提高, 喷雾贯穿距增大, 核心区贯穿距占比(RP)提高, 但超高压喷射下增幅都相对较小; 提高喷射压力, 核心区锥角出现小幅度增加; 提高喷射压力, 喷雾投影面积增大, 核心区面积占比(RA)减小, 雾化程度显著提高．
The aim of this study was to explore the spray macroscopic characteristics of gasoline direct injection(GDI)injector fueled with ethanol under ultra-high injection pressure conditions. Spray images were obtained by schlieren and high-speed photography technology under the injection pressure from 10 MPa increasing to 60 MPa，and the various parameters including spray development process，penetration，cone angle，and spray area were systematically analyzed. The results indicate that branch-like structures occurring time decreases，but the branch-like structure of spray becomes a bit blurry under ultra-high injection pressure. The penetration of spray and its liquid core increases rapidly in the initial stage，but growth rate decreases significantly in the middle stage. Spray penetration and penetration ratio of liquid core(RP)increase with the increase of injection pressure，but the increases are relatively small under ultra-high injection pressure conditions. The liquid cone angle at core area increases a little with increasing injection pressure. Spary area increases，area ratio of liquid core(RA)decreases，and the degree of atomization enhances significantly with the increase of the injection pressure