Corrections to facilitate planar imaging of particle concentration in particle-laden flows using Mie scattering, part 1: collimated laser sheets.
Corrections to facilitate planar imaging of particle concentration in particle-laden flows using Mie scattering, part 1: collimated laser sheets.
复制标题
使用米氏散射进行修正，以促进颗粒负载流中颗粒浓度的平面成像，第 1 部分：准直激光片。
作者：
P. Kalt;C. Birzer;G. Nathan
平面散射比浊法是一种基于激光的技术，其对从颗粒散射的光进行成像以提供关于这些颗粒的局部数密度的信息。在许多实际感兴趣的种子流中，例如煤粉火焰，颗粒负载足够高，使得入射激光束严重衰减。因此，在这些流动中的测量是困难的，并且在这些条件下可获得的数据有限。在不同浓度的球形颗粒悬浮液中进行了激光衰减实验。这是用来制定一个漫散射和激光片消光效应的校准。通过大量播种，光散射介质的光分布模型也开发和实验结果进行了比较。它表明，散射信号可以被认为是成比例的本地颗粒浓度乘以入射激光功率。入射激光功率作为由遮蔽引起的衰减的函数而变化。因此，平面浊度图像的校正扩展了该技术，以提供瞬时颗粒浓度测量的伪定量数据。
Planar nephelometry is a laser-based technique of imaging the light scattered from particles to provide information about the local number density of these particles. In many seeded flows of practical interest, such as pulverized coal flames, particle loadings are sufficiently high for the incident laser beam to be severely attenuated. Measurements in these flows are therefore difficult, and limited data are available under these conditions. Laser attenuation experiments were conducted in suspensions of spherical particles in water at various concentrations. This is used to formulate a calibration for the effects of diffuse scattering and laser sheet extinction. A model for the distribution of light through a heavily seeded, light-scattering medium is also developed and is compared with experimental results. It is demonstrated that the scattered signal may be considered proportional to the local particle concentration multiplied by the incident laser power. The incident laser power varies as a function of the attenuation by obscurement. This correction for planar nephelometry images thus extends the technique to provide pseudoquantitative data for instantaneous particle concentration measurements.