Particle Sizing and Velocity Measurement in Multiple Scattering Flowing Media

abstractcts - 0120846 r。许多颗粒处理系统，如制药、化工、石油和其他行业的应用，都需要对液体中悬浮颗粒的物理特性进行研究。动态光散射已经成功地应用于实验室，但在涉及颗粒传输的工业过程中取得了有限的成功。虽然对于单个散射光，可以准确地确定颗粒大小。然而，在悬浮运输中发生的多次散射妨碍了精确的颗粒大小或速度测量。为了解决这一问题，以往的努力主要集中在发展多分散问题的相关理论，但收效甚微。本文提出了一种新的方法，将两个角距较小但有限的探测器发出的信号相互关联，只检测单个散射散斑图。该方法是结合“流动抑制”技术提出的，其中使用垂直于流动方向的散射波矢量来避免由于流体速度引起的干扰，从而可以更准确地测量流动悬浮液中的粒径。亚微米粒子在低速下的初步结果显示出一定的潜力。

AbstractCTS-0120846R. Dougherty, University of Kansas Center for Research Inc.Physical characterizing of the suspended particles in liquid is required for many particulate processing systems such as applications in pharmaceutical, chemical, oil, and other industries. Dynamic light scattering has been successfully used in the laboratory with limited success in industrial processes involving particulate transport. Although for single scattered light, the particle size can be accurately determined. However, multiple scattering occurring in suspension transport prevents accurate particle size or velocity measurements.To resolve this problem, previous efforts have been focused on development of correlation theories in multiple scattered problem with limited success. A novel approach is proposed here where the signals from two detectors with small but finite angular separation are cross-correlated to detect only the single scattered speckle patter. This method is proposed in combination of 'flow suppression' technique where the scattered wave vector perpendicular to the flow direction is used to avoid the disturbance due to the fluid velocity, allowing more accurate measurement of the particle size in a flowing suspension. The preliminary results for submicron particles at low velocities show some potential.