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遮光度对激光散射法粒径测量影响及修正

工程热物理学报 2024年第9期45卷 2696-2701页

作者：苏格毅孙存金邓飞苏明旭上海理工大学能源与动力工程学院上海市动力工程多相流动与传热重点实验室上海200093

针对液固两相流体系分散相粒径表征中复散射导致低估粒度问题,建立基于蒙特卡罗(Monte Carlo)方法的激光散射模型,研究高遮光度下颗粒光散射特性。为验证模型准确性,搭建一套散射光能分布和遮光度同步测量系统,对不同浓度聚苯乙烯悬浮... 详细信息

针对液固两相流体系分散相粒径表征中复散射导致低估粒度问题,建立基于蒙特卡罗(Monte Carlo)方法的激光散射模型,研究高遮光度下颗粒光散射特性。为验证模型准确性,搭建一套散射光能分布和遮光度同步测量系统,对不同浓度聚苯乙烯悬浮液进行试验。结果表明:未考虑复散射时,蒙特卡罗模型与传统模型散射光能吻合度良好。考虑复散射时,随着遮光度增加,散射光能曲线逐渐偏移,反演误差逐渐变大。遮光度为0.15~0.20,反演误差在5%以内。然而,遮光度为0.55~0.60,反演误差超过13%。进行误差修正,通过蒙特卡罗方法建立的激光散射模型构造系数矩阵,对粒径2.6μm颗粒的实验谱反演,误差在3%以内,表明该模型可在高遮光度下准确反演粒度。

关键词：复散射激光散射法蒙特卡罗方法遮光度反演

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基于蒙特卡罗模型的高浓度浆液细度在线测量

仪器仪表学报 2024年第1期45卷 170-179页

作者：张世玮刘鸿彬陈朝雷田昌苏明旭上海理工大学能源与动力工程学院上海200093 上海市动力工程多相流动与传热重点实验室上海200093

近年来颗粒粒径测量问题受到了国内外的广泛研究。针对燃煤电厂高浓度脱硫石灰石浆液细度在线测量,将基于蒙特卡罗方法的声衰减模型拓展至高浓度范围,高浓度蒙特卡罗模型(HC-MCM)预测衰减系数与实验测量值相吻合。构建HC-MCM矩阵用于颗... 详细信息

近年来颗粒粒径测量问题受到了国内外的广泛研究。针对燃煤电厂高浓度脱硫石灰石浆液细度在线测量,将基于蒙特卡罗方法的声衰减模型拓展至高浓度范围,高浓度蒙特卡罗模型(HC-MCM)预测衰减系数与实验测量值相吻合。构建HC-MCM矩阵用于颗粒粒径分布的反演可减小计算时间,且差分进化算法的计算结果与设定粒径和分布宽度的相对误差小于1%。搭建基于透射和反射法的双模式超声检测装置并开发软件测量系统,加工适用于高浓度浆液细度测量的透射传感器和超声探针,依托燃煤电厂完成长达168 h的浆液细度在线测量实验。结果表明,两种模式超声衰减谱的变化趋势和数值大小基本吻合。粒径分布参数D_(V50)与激光粒度仪测量结果的相对误差小于8%,其粒径分布满足燃煤电厂成品石灰石浆液的细度要求。

关键词：高浓度石灰石浆液蒙特卡罗模型超声测量粒径分布

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混合颗粒系消光模型及反演研究

过程工程学报 2024年第9期24卷 1070-1079页

作者：邓飞苏格毅黄茜孙存金苏明旭上海理工大学能源与动力工程学院上海200093 上海市动力工程多相流动与传热重点实验室上海200093

在单一颗粒系中,消光光谱法颗粒粒径测量模型通常基于Mie散射理论和朗伯-比尔定律(Lambert-Beer Law)构建。但由多种颗粒物构成的混合颗粒系消光特性更为复杂,颗粒粒径及分布、折射率、颗粒配比均会影响消光谱,传统模型不再适用。本工... 详细信息

在单一颗粒系中,消光光谱法颗粒粒径测量模型通常基于Mie散射理论和朗伯-比尔定律(Lambert-Beer Law)构建。但由多种颗粒物构成的混合颗粒系消光特性更为复杂,颗粒粒径及分布、折射率、颗粒配比均会影响消光谱,传统模型不再适用。本工作将消光截面按混合比等效,构建了一种混合颗粒消光模型。对于多种混合颗粒系进行消光谱数值计算,将混合颗粒系分为单分散和多分散两种情况,分别探讨了颗粒粒径、折射率、混合比及分布参数对消光光谱影响规律。研究了混合颗粒系粒径、分布参数和混合比多参数同步反演问题,搭建消光谱测量系统并配置混合比为0.25, 0.5及0.75的二氧化硅和聚苯乙烯混合颗粒悬浮液进行实验,采用改进差分进化算法对实验谱进行反演。结果表明,混合消光模型预测与实验消光谱吻合,均方根误差小于0.08;实现了在不同混合比条件下多分散混合颗粒系的多参数同步反演,粒径和混合比的最大反演误差绝对值分别为7.44%和7.48%,均小于单分散假定时混合颗粒系参数反演误差绝对值,分布参数结果较好地反映了实验样品颗粒粒径分布较窄的特点。

关键词：混合颗粒系朗伯-比尔定律消光谱混合比反演

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超声速差法平面叶栅流场试验和数值研究

中国电机工程学报 2024年第2期44卷 652-658,I0018页

作者：俞天阳张世玮却依飞马良田昌苏明旭上海理工大学能源与动力工程学院上海市杨浦区200093 上海市动力工程多相流动与传热重点实验室上海市杨浦区200093

针对平面叶栅狭小通道中流场非接触测量难题,提出一种基于超声速差原理的二维流场测量方法。设计一种2×4超声波斜、平口换能器组合阵列,研制一套多通道超声法测量和气流速度场重建系统。开展平面叶栅流场测量试验,成功获取了3种不同进... 详细信息

针对平面叶栅狭小通道中流场非接触测量难题,提出一种基于超声速差原理的二维流场测量方法。设计一种2×4超声波斜、平口换能器组合阵列,研制一套多通道超声法测量和气流速度场重建系统。开展平面叶栅流场测量试验,成功获取了3种不同进口速度条件下流道二维速度场。利用COMSOL Multiphysics中CFD模块同步开展叶栅流场数值模拟,并与试验结果对比。结果表明:超声测量与数值模拟结果较为接近,速度大小和偏转角误差均在5%以内,较好地反映叶栅通道的流动特点。提出的超声测量技术有望进一步用于高马赫数流场研究。

关键词：二维超声阵列速差法平面叶栅流场测量数值模拟

Resonance scattering characteristics of double-layer spherical particles

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Particuology 2012年第1期10卷 117-126页

作者： Xuejin Dong mingxu su Xiaoshu Cai Institute of Particle and Two-Phase Flow Measurement University of Shanghai for Science and Technology Shanghai 200093 China

Based on the principle of ultrasonic resonance scattering, sound-scattering characteristics of double-layer spherical particles in water were numerically studied in this paper. By solving the equations of the scat- tering matrix, the scattering coefficient determined by the boundary conditions can be obtained, thus the expression for the sound-scattering function of a single double-layer spherical particle can be derived. To describe the resonance scattering characteristics of a single particle, the reduced scattering cross section and reduced extinction cross section curves were found through numerical calculation. Similarly, the numerically calculated sound attenuation coefficient curves were used to depict the resonance scattering characteristics of monodisperse and poIydisperse particles. The results of numerical calculation showed that, for monodisperse particles, the strength of the resonance was mainly related to the particle size and the total number of particles; while for polydisperse particles, it was primarily affected by the particle size, the coverage of the particle size distribution and the particle concentration.

关键词： UltrasonicResonance scatteringDouble-layerPolydisperseVisco-elastic

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真空弧阴极放电液滴光散射测量

激光与光电子学进展 2024年第15期61卷 148-154页

作者：孙存金苏格毅于海涛田昌董攀苏明旭上海理工大学能源与动力工程学院上海市动力工程多相流动与传热重点实验室上海200093 上海理工大学理学院上海200093 中国工程物理研究院流体物理研究所四川绵阳621900

对真空弧放电过程金属液滴进行测量,提出一种基于Mie散射理论在线测量方法。以650 nm红光激光器为光源,并搭配相机同步控制装置,搭建真空弧金属液滴在线测量系统,利用非独立模式差分进化算法反演出颗粒粒径分布。通过4种聚苯乙烯乳胶球... 详细信息

对真空弧放电过程金属液滴进行测量,提出一种基于Mie散射理论在线测量方法。以650 nm红光激光器为光源,并搭配相机同步控制装置,搭建真空弧金属液滴在线测量系统,利用非独立模式差分进化算法反演出颗粒粒径分布。通过4种聚苯乙烯乳胶球标准颗粒实验对测量系统准确性进行验证,测量误差在5%以内;在不同放电电流、放电脉宽条件下对4种阴极金属材料的金属液滴进行在线测量。测量结果表明:对于同种金属,放电脉宽或放电电流的增大对金属液滴粒径大小影响不明显;相同放电电流和放电脉宽下,阴极金属的材料对粒径分布具有明显影响,同一工况下铝、铁、钛、钼液滴中位径分别为1.55μm、1.25μm、1.15μm、0.75μm。实验结果可为研究真空弧阴极放电过程提供参考。

关键词：真空弧阴极 Mie散射金属颗粒粒径分布在线测量

In-line imaging measurements of particle size,velocity and concentration in a particulate two-phase flow

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Particuology 2014年第2期12卷 106-113页

作者： Xiaozhen Chen Wu Zhou Xiaoshu Cai mingxu su Hailong Liu Institute of Particle and Two-phase Flow Measurement University of Shanghai for Science and Technology

A novel method is developed for in-line measurements of particle size, velocity and concentration in a dilute, particulate two-phase flow based on trajectory image processing. The measurement system consists of a common industrial CCD camera, an inexpensive LED light and a telecentric lens. In this work, the image pre-processing steps include stitching, illumination correction, binarization, denoising, and the elimination of unreal and defocused particles. A top-hat transformation is found to be very effective for the binarization of images with non-uniform background illumination. Particle trajectories measured within a certain exposure time are used to directly obtain particle size and velocity. The particle concentration is calculated by using the statistics of recognized particles within the field of view. We validate our method by analyzing experiments in a gas-droplet cyclone separator. This in-line image processing method can significantly reduce the measurement cost and avoid the data inversion process involved in the light scattering method.

关键词： In-line measurements Particle trajectory Image processing Multi-parameters

Optimization of regularization parameter of inversion in particle sizing using light extinction method

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China Particuology 2007年第4期5卷 295-299页

作者： mingxu su Feng Xu Xiaoshu Cai Kuanfang Ren Jianqi Shen Institute of Particle and Two Phase Flow Measurement Technology University of Shanghai .for Science and Technology Shanghai 200093 China LESP UMR6614/CORIA CNRS-Universite France INSA de Rouen 76801 France

In particle sizing by light extinction method, the regularization parameter plays an important role in applying regularization to find the solution to ill-posed inverse problems. We combine the generalized cross-validation （GCV） and L-curve criteria with the Twomey-NNLS algorithm in parameter optimization. Numerical simulation and experimental validation show that the resistance of the newly developed algorithms to measurement errors can be improved leading to stable inversion results for unimodal particle size distribution.

关键词： Particle size analysis Light extinction Inversion algorithm Regularization parameter

Modeling and prediction of ultrasonic attenuations in liquid-solid dispersions containing mixed particles with Monte Carlo method

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Particuology 2019年第2期17卷 84-91页

作者： Jianfei Gu Fengxian Fan Yunsi Li Huinan Yang mingxu su Xiaoshu Cai Institute of Particle and Two-Phase Flow Measurement/Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology Shanghai 200093 China

We develop a theoretical model for predicting the ultrasonic attenuation in the liquid-solid system containing mixed particles. The ultrasonic attenuation coefficient is obtained by counting the number of phonons that reach the receiver. Using the Monte Carlo method (MCM), numerical simulations were performed to predict the ultrasonic attenuations with not only a single particle type but also monodisperse and polydisperse mixed particles. The simulation results for the systems with a single particle type were compared with various standard models. The results show that they agree well at relatively low particle volume concentrations (within 10%). For systems with mixed particles, the particle volume concentrati on was found to in crease to around 10%, and the variation of the ultrasonic attenuation agai nst the mixing ratio yields a nonlinear trend. Moreover, the ultrasonic attenuation is significantly affected by particle properties. The numerical results also show that both the particle type and particle size distribution should be carefully taken into account in the dispersions with polydisperse mixed particles, where the MCM can give a more direct description of the physics of sound propagation compared with the conventional models.

关键词： Ultrasound Ultrasonic attenuation Monte Carlo method Particle size measurement