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particle sizing in dense two-phase droplet systems by ultrasonic attenuation and velocity spectra

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science china(Technological sciences) 2009年第6期52卷 1502-1510页

作者： su mingxu cai xiaoshu xue minghua DONG LiLi xu feng institute of particle and two-phase flow measurement University of Shanghai for Science and TechnologyShanghai 200093China

Size and size distribution of particles in particulate two-phase flow play an important role in a wide variety of industrial areas,while their measurement still remains a hard task till *** wave as a mechanical vibration contains plenty of information about medium when it passes *** the size distribution could be extracted from the measured ultrasonic attenuation and velocity spectra by means of well established models and data processing *** paper contributes to the extraction of information of droplet size of a two-phase fat emulsion simultaneously from signals of broad-band ultrasonic attenuation and velocity *** to the formulated single particle scattering model,the relationship between particle size distribution and ultrasonic spectrum is *** sensitivities of ultrasonic spectra to the variation of particle size are ***-guishing features for attenuation and velocity spectra are *** calculations of inversion by optimum regularization factor method are carried out to yield the typical numerical results for *** on the proposed inversion algorithm and theoretical model,a fat emulsion sam-ple with a volume fraction up to 20% is measured and *** validate the proposed ultrasonic spectrum particle sizing method,the results are compared to those obtained from optical measure-ment.

关键词： two-phase flow ultrasonic particle sizing inversion

A study on measuring distribution of nanoparticle size based on ultrasonic attenuation spectrum

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Chinese Journal of Acoustics 2011年第3期30卷 261-271页

作者： HOU Huaishu su mingxu cai xiaoshu institute of particle and two phase flow measurement University of Shanghai for Science and Technology Shanghai 20093 College of Mechanical Engineering Shanghai Institute of Technology Shanghai 201418

Through varying the ultrasonic path length, the ultrasonic attenuation spectrum of the nanometer particle suspensions is measured. Based on the McClements and BLBL model, the Optimum Regularization Technique is employed to inverse the distribution of particle size for nanometer particles. Experiments are carried out to measure the distribution of particle size of aqueous nanometer titanium dioxide suspension with volume fraction of 1%. The ultrasonic measurement results show good consistence with those from TEM （Transmission Electron Mi- croscope） and centrifugal sedimentation particle size analyzers, which indicate that measuring distribution of the particle size of nanometer particles with the ultrasonic attenuation spectrum is feasible and reliable.

关键词：纳米粒子悬浮液超声波测量超声衰减粒子尺寸分布纳米二氧化钛纳米颗粒粒度分析仪路径长度

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

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

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

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

Fast nanoparticle sizing by image dynamic light scattering

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Particuology 2015年第2期13卷 82-85页

作者： Chengze xu xiaoshu cai Jie Zhang Lili Liu institute of particle and two-phase flow measurement University of Shanghai for Science and Technology

In this paper, an image dynamic light scattering method for nanoparticle sizing is introduced. The spatial distribution of the scattered lights from nanoparticles undergoing Brownian motion was captured at a high frame rate by a digital camera within one second, which is considerably faster than the conven- tional photon correlation spectroscopy method. The captured series of photographs were meshed into thousands of small units for calculating the intensity autocorrelation functions in parallel. Experimental results from the measurements of three reference nanoparticle samples （27, 80, and 352 nm in diameters） demonstrated the feasibility of this method.

关键词： Nanoparticle sizing Image dynamic light scattering Real-time acquisition Brownian motion

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燃烧与流场在线测量诊断方法研究进展

实验流体力学 2014年第1期28卷 12-20页

作者：蔡小舒周骛杨荟楠杨斌陈军苏明旭李俊峰上海理工大学颗粒与两相流测量研究所上海200093

介绍了上海理工大学颗粒与两相流测量研究所近年来在燃烧和流场在线测量诊断技术方面的研究进展,包括:改进基于光纤光谱仪的火焰辐射温度测量技术,提高火焰温度的测量精度与范围并反演出火焰辐射率及液体燃料组分;辐射与吸收光谱相结合... 详细信息

介绍了上海理工大学颗粒与两相流测量研究所近年来在燃烧和流场在线测量诊断技术方面的研究进展,包括:改进基于光纤光谱仪的火焰辐射温度测量技术,提高火焰温度的测量精度与范围并反演出火焰辐射率及液体燃料组分;辐射与吸收光谱相结合测量脉冲燃烧火焰温度和水蒸气浓度;基于激光诱导荧光法测量喷雾液滴温度;强烟尘水滴干扰条件下基于差分吸收光谱法(DOAS)测量排放污染气体(SO2和NOx)浓度;基于饱和蒸汽原理的光谱法研制汞连续排放监测标准系统;光谱法与图像法结合测量高温物体温度场;基于单帧单曝光图像法测量多相流速度场与粒度分布;基于可调谐半导体激光吸收光谱法(TDLAS)同步测量液态纯水水膜蒸发过程中液态参数(水膜厚度及温度)与气态参数(水膜上方水蒸气的温度)等。

关键词：在线诊断流场燃烧测量温度

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基于连续超声波测量气泡参数的实验研究

能源研究与信息 2019年第4期35卷 227-233页

作者：时文龙苏明旭李潭陈晶丽蔡小舒上海理工大学颗粒与两相流测量研究所/上海市动力工程多相流动与传热重点实验室上海200093

研究了一种基于声阻原理的测量液体中毫米级气泡粒度、速度并能同时计数的方法。超声波在含气泡液体中传播时,由于气泡和液体间声阻抗差极大,致使其在气泡表面发生强烈反射/散射,阻碍了声波通过。利用频率为200 kHz的超声连续波,采用一... 详细信息

研究了一种基于声阻原理的测量液体中毫米级气泡粒度、速度并能同时计数的方法。超声波在含气泡液体中传播时,由于气泡和液体间声阻抗差极大,致使其在气泡表面发生强烈反射/散射,阻碍了声波通过。利用频率为200 kHz的超声连续波,采用一发一收式测量,对某润滑油中的气泡进行测量,实验中气泡大小为2~6 mm,速度在0.10~0.30 m·s^−1之间,气泡通过测量区的频率为5~10 Hz。通过分析实验数据的波形幅值与气泡粒度、波形转变时间与气泡速度、通过数之间的对应关系,并利用图像法进行了标定和校验。实验结果表明,利用连续超声波可以测得油中连续通过的气泡,其原理和测量装置简单,测量结果稳定。

关键词：超声声阻连续波气泡计数