光复散射对消光法粒径测量的影响:复散射模型与数值模拟

The Affect of Light Multiple Scattering on Particle Sizing by Using Light Extinction Method

复散射效应在光散射颗粒测量中不仅重要 ,且尚未得到很好解决。采用蒙特卡罗方法 ,对不同的光波长 ,颗粒浓度以及收接器条件下的光复散射进行了数值模拟 ,数值算法程序经与四通量模型进行对比验证 ,数值结果与单散射条件的郎伯比尔模型进行比较 ,进而讨论了复散射效应对消光法颗粒粒径测量影响。表明复散射对消光法颗粒测量的影响不仅取决于颗粒系自身的浓度 ,而且接收器的几何尺寸和接收位置起着非常重要的作用 ,减小颗粒介质层厚度和减小光接收器接收面积 ,增大接收距离以及减小接收角都能减小复散射效应对消光法粒径测量的影响。

By using Monte Carlo method, author present an exact prediction of light transmittance in multiple scattering condition for different configuration: concentrations, wavelengths and size and receiving angle of the detector. The program is verified by comparing with four-flux model. With comparison to the prediction of the Lambert-Beer law, how the multiple scattering influences the result of particle sizing is discussed. Decreasing area of detector, limiting the collection angle and increasing the distance from plane of media to detector can weaken the effect of multiple scattering on particle sizing.