Study of vortex structure in high number density spray based onturbulence correlation

用激光双焦点测速仪（L2F）测量了柴油喷雾器从直径为0.113mm的喷雾器中间歇喷射到大气中的速度和液滴大小。钢轨压力设定为80MPa，螺线管通电时间设定为3.0ms。三个测量位置分别位于距离喷嘴出口6,9和12mm的平面上。采用基于相关的开槽技术对湍流的速度积分尺度、大小积分尺度和数据速率积分尺度进行了计算。湍流在速度上的积分尺度大于在尺寸和数据速率上的积分尺度。各尺度随液滴飞行距离的增加而增大。采用相位多普勒技术对柴油机喷油器间歇喷射到大气中的液滴的速度、大小和飞行角进行了测量。在喷雾轴附近，液滴除了具有喷雾轴方向速度分量外，还具有径向向外速度分量。射流轴向的速度分量随半径的增大而减小。可以理解，向后对角线观察到的喷雾轨迹来自于喷雾轴附近的速度差。从喷雾外围向内移动的液滴改变了其速度矢量的方向，从径向向内到喷雾轴。上面提到的液滴运动的组合被认为构成了一个漩涡。

A laser 2-focus velocimeter (L2F) was used for measurements of velocity and size of droplets in diesel sprays injected intermittently into the atmosphere from aninjector with an orifice of 0.113mm in diameter. The rail pressure was set at 80MPa, and the solenoid energizing time was set at 3.0ms. Three measurement positions were located on the plane 6, 9 and 12 mm from the nozzle exit. The integral scale of turbulence in velocity, the one in size and the one in data rate were evaluated by correlation based slotting technique. The integral scale of turbulence in velocity is larger than the one in size and data rate. Every scale increases with the distance of droplet flight.Phase Doppler technique was used for the measurements of the velocity, size and flight angle of droplets in diesel sprays injected intermittently into the atmosphere from an injector. In the vicinity of the spray axis, droplets have the components of radially outward velocity in addition to that of the spray axis direction velocity. And the velocity components of spray axis direction decreased with the radius. It is understood that the trajectory of the spray observed diagonally backward come ftom the difference in velocities near the spray axis. Droplets which move inward from the periphery of the spray change their directions of velocity vector from the radially inward to the spray axis. A combination of the droplet movements which were mentioned above is considered to make up a vortex.