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Development of Simultaneous Non-intrusive Measurement of Size, Flowing Attitude and Velocity of Arbitrarily Shaped Particle.

开发同时非侵入式测量任意形状颗粒的尺寸、流动姿态和速度。

基本信息

批准号：
07555073
负责人：
MAEDA Masanobu
金额：
$ 5.12万
依托单位：
Keio University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07555073/
关键词：
Laser technique Non-intrusive measurement Velocity measurement Shape measurement Non-spherical particle LDV PDA

项目摘要

The sizing of arbitrarily shaped particles is of technical interest and accurate determination of their equivalent diameter is important, because most particles in industrial processes are non-spherical. A reliable measuring technique has been demanded for improvement of equipment with high efficiency. In general, motion of non-spherical particle in fluid is governed by drag and inertia forces. The evaluation of equivalent diameter of non-spherical particle is not relevant due to the lack of effective measuring techniques. The purpose of the present investigation is to develop the measuring technique for non-spherical particles in flow and to establish a suitable signal processing technique, which provided velocity, size shape, and attitude and trajectory of particle. The measurements were implemented with free falling flow and confined jet flow. The effect of non-sphericality on particle dispersion was presented by these experiments, and also the performance and accuracy of the presen … More t technique were confirmed by the practical application.The present instrument consisted of a Laser Doppler Velocimeter and a receiving optics and a shadow image processor unit with a linear photo sensor array placed at the focal plane corresponding to the measuring volume. The array sampled one-dimensional slices of moving two-dimensional shadow at the pre-defined sampling frequency. The time series of the on-dimensional slices and the simultaneously measured particle velocity were used for reconstruction of the two-dimensional shadow image. From the provided shadow area the particle size was determined. Measurement accuracy of sizing was estimated at about 3% for spherical particles and 10% for non-spherical particles. The measuring system also provided spatial position of a particle traveling through the measuring volume.The experiments in a confined jet flow with Reynolds number of 14700, in which two-component velocities, size and number density of particle were measured, indicated that the axial component of mean velocities of non-spherical particle was smaller than that of spherical particle which had a almost same terminal velocity, and that radial mean square displacement of non-spherical sarticles estimated form their number density measurements was larger than that of spherical particles. It was concluded from the results that non-spherical particle behaved differently form spherical particles in downstream of the jet, and longer resident time of non-spherical particle in the jet flow caused larger radial dispersion. Less

由于工业过程中的大多数颗粒都是非球形的，因此对任意形状颗粒的大小进行测量具有重要的技术意义，并且准确确定其当量直径也很重要。为了提高设备的使用效率，需要一种可靠的测量技术。一般情况下，非球形颗粒在流体中的运动受阻力和惯性力的控制。由于缺乏有效的测量技术，对非球形颗粒当量直径的评价并不重要。本研究的目的是发展对流动中非球形颗粒的测量技术，并建立一种合适的信号处理技术，以提供颗粒的速度、尺寸、形状、姿态和轨迹。测量采用自由落体流和受限喷流两种方式。通过这些实验，给出了非球形性对粒子分散的影响，以及现有…的性能和精度该仪器由激光多普勒测速仪、接收光学元件和阴影图像处理单元组成。阴影图像处理单元将线性光传感器阵列放置在与测量体积对应的焦平面上。该阵列以预定的采样频率对运动的二维阴影的一维切片进行采样。利用二维切片的时间序列和同时测量的粒子速度重建二维阴影图像。根据提供的阴影区域确定颗粒大小。球形颗粒的测量精度约为3%，非球形颗粒的测量精度约为10%。在雷诺数为14700的受限射流中，测量了颗粒的两组分速度、尺寸和数密度，结果表明，非球形颗粒平均速度的轴向分量小于末端速度几乎相同的球形颗粒，而由数密度测量得到的非球形颗粒的径向均方位移大于球形颗粒。结果表明，非球形颗粒在射流下游的行为与球形颗粒不同，非球形颗粒在射流中停留时间越长，径向弥散越大。较少