基于二阶滤波器的消光起伏谱颗粒测量结果

消光起伏频谱法是一种新的测量两相流系统中颗粒粒径分布和浓度的方法,装置简单,操作方便,适合实时、在线测量。采用二阶低通滤波器对起伏的透射率信号分析,得到消光起伏频谱实验数据,并利用改进的Chahine循环方法计算得到颗粒的粒径分布和浓度信息。重点讨论高浓度情况,包括对特征函数频率响应的修正和对其阶高修正两个方面,得到修正参量并运用到反演算法中从而得到正确的测量结果。测量结果表明,通过高浓度修正,消光起伏频谱法可以在很大的颗粒浓度动态范围得到合理的测量结果,其可测颗粒最大体积分数视颗粒的大小而定。

Measurements on Particle by Transmission Fluctuation Spectrometry Using Second Order Filter

The) transmission fluctuation spectrometry(TFS),a new method can measure the particle size distribution(PSD) and particle concentration simultaneously in two-phase fluid system.With simple optical arrangement and easy operation,the method can be applied to real-time,online measurements.The transmission signal with fluctuations are analyzed by using a second order low pass filter(LPF),and the experimental data of transmission fluctuation spectra in the frequency domain are obtained.The particle size distributions and concentrations are extracted from the experimental data with the modified Chahine iterations.Effects on the spectra of transmission fluctuations of the high concentration are discussed.The high concentration correction includes frequency response to characteristic function and step height of the transition function.Parameters for the high concentration correction are achieved and further employed in the inversion algorithm,and reasonable measurement results are obtained.Analysis to the measurement data shows that,with the high-concentration correction,the particle size distribution and particle concentration can be recovered within a broad dynamic range and the largest measurable particle volume concentration depends on the particle size.