汽油液膜喷射和圆喷射雾化过程的PIV测量对比研究

利用PIV设备，在相同喷射压力和不同喷射脉冲下对分属液膜射流和圆形射流两种理论喷射类型的典型喷油器-涡旋喷孔和双喷孔喷油器的汽油雾化性能进行对比研究。研究表明：涡旋射流的油锥前锋以及外缘部分的油膜破碎均匀且雾化效果较好；双孔射流的雾化油滴粒子都集中分布在喷射中心线上，且油膜连接比较完整，雾化效果较差。涡旋射流雾化粒子的速度场分布比较膨胀和发散，而双孔射流的雾化粒子集中分布在中心线上（与浓度分布规律一致）；相同时刻，双孔射流雾化粒子的速度绝对值最大值均明显大于涡旋喷孔。针对两种喷嘴都存在：喷射过程中越靠近喷嘴出口处的区域速度绝对值越大，而停喷后，高速区都集中在喷雾的前锋；在一定的喷射压力下，喷射结束时的贯穿距离与喷射脉宽基本呈正比关系。

The contrastive study of the process of gasoline liquid-film spray and cylindrical spray with PIV measurements

The PIV is applied to research contrastively the gasoline spray performance of the swirl injector and the double-jet holes injector which respectively belong to the academic spray model called liquid-film spray and cylindrical spray. The result shows that the front and the edge of the oil-film of spray from the swirl injector break up adequately and the process of spray is complete~ the gasoline particles sprayed from double-jet injector are distributed densely on the spray central line and the oil-film from the injector keep integrative and the process of spray is in- complete comparatively. The distribution of the speed-field of the particles sprayed from the swirl injector is inflatable and emanative, and the distribution of the speed-field of the particles sprayed from the double-jet injector is focused on the spray central line （in coincidence with its concentra- tion distribution） at the same time, the maximum of absolute value for the speed of the particles sprayed from the double-jet injector are higher than the swirl injector; both the two injectors have the similar characteristics that the areas which are closer to the injectors contain more high-speed oil particles, but the high speed area is distributed on the front of the spray when the injection is stop ; under the same injection pressure, the spray distance is in direct ratio from the pulse-width of injection.