Research development of Interferometric Laser Imaging for Droplet Sizing with PIV and flow analysis of spray

对单个颗粒特性的详细研究对于理解诸如燃料或液体的汽化、冷却和气泡的溶解过程等流动结构是必要的。流体中的颗粒浓度通常是不均匀的，这取决于周围的流场和颗粒直径。虽然在不同位置处的同时现象之间的相互作用是相当显著的，但是没有常规的技术或商业设备可以测量颗粒浓度的空间波动和颗粒的个体特性。相位多普勒测速仪（PDA）是一种颗粒粒径和速度的点式测量技术，但它在给出颗粒的空间相关性和应用非定常流方面存在困难。粒子图像测速仪（PIV）是一种提供速度矢量并能识别流场空间结构的平面技术。由于PIV技术假设了颗粒局部运动的相似性，颗粒的尺寸分布及其与速度的相关性给出了颗粒图案的不规则询问。显微镜观察是另一种测定颗粒尺寸的方法，但测量面积很小。本研究的目的是开发一种新的测量技术，通过集成独特的光学系统，高速图像采集系统，全自动数据处理软件，可以应用喷嘴附近的喷雾流的高浓度区域。

The detail investigation of the individual particle characteristics is necessary to understand the flow structure such as fuel or liquid vaporization, cooling and dissolution process of gas bubbles. Particle concentration in fluid is ordinarily inhomogeneous depending on the surrounding flow field and particle diameter as well. Although the interaction between simultaneous phenomena at the different position is quite significant, there is no conventional technique or no commercial equipment that can measure the spatial fluctuation of particle concentration and individual characteristics of particle. Phase Doppler Anemometer (PDA), which is the point measurement technique for the particle diameter and velocity, has difficulty in giving the spatial correlation of particles and in applying the unsteady flow. Particle Image Velocimeter (PIV) is the planar technique that provides the velocity vector and permits to identify the spatial structure of flow. Since the PIV technique assume the similarity of the local particle motion, size distribution of particle and their correlation with the velocity gives an irregular interrogation of particle patterns. Microscopic observation is another method to determine the particle size, however the measuring area is quite small. The objective of the present study is to develop the new measurement technique that can apply the high concentration region of spray flow near the nozzle by integrating the unique optical system, high speed image acquisition system, fully automated data processing software.