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Numerical　Study　of　the　Feed　Flow　and　Its　Influence　on　the　separation　efficiency　of　a　Gas　Centrifuge

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Tsinghua Science and Technology 1996年第1期1卷 61-65页

作者：傅瑞峰陈伟波应纯同

In a Zippe-type 3-pole gas centrifuge, feed gas is introduced through a sonic nozzle into the rarefied region in the rotor. Introduction of the nonrotating feed gas will slow the whirl flow and introduce a secondary recirculating flow in the meridian plane. The effects of feed gas on the output of a gas centrifuge are investigated. The non-linear. axisymmetric N-S equations are used to calculate the secondary flow induced by the feed gas. Three types of numerical schemes. an implicit scheme similar to the Beam-Warming scheme. an implicit unfactorized scheme and an improved Newton-Raphson scheme are used. The Cohen separation theory with axial variation is used forcalculating the isotope concentration. Optimization of the output is achieved by automatic variation of the weighting factors for a number of linear flow solutions which can be superimposed. A Rome type centrifuge is analyzed as an example. Results show the recirculating flow caused by the feed gas. especially the acceleration loss. has an important effect on the output of a gas centrifuge.

关键词： feed flow: Navier-Stokes equations separation efficiency gas centrifuge secondary recirculating flow

Effects of the inlet particle spatial distribution on the performance of a gas-solid cyclone separator

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Particuology 2024年第2期85卷 133-145页

作者： Yuge Yao Manxia Shang Xiwei Ke Zhong Huang Tuo Zhou Junfu Lyu Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Energy and Power EngineeringTsinghua UniversityBeijing100084China

The present study was aimed at the inlet particle spatial distribution of a gas-solid separator with high solid loading and investigated its effects on cyclone performance and the inner flow *** flow fields of a cyclone with different rectangular particle flow areas on the inlet surface were numerically simulated using a four-way coupling *** simulated results indicate that reducing the inlet particle flow area and lowing the inlet particle position can effectively reduce the scattered particles inside the cyclone separator and enhance the separation *** gathering the particles to the centerline can also weaken the particle *** particles near the roof account for the swirling particle ceiling *** inlet particle spatial distribution affects the pressure drop mainly by affecting the gas tangential velocity in the cylinder ***,compared to the hori-zontal particle distribution on the inlet surface,the vertical particle distribution has greater effects on cyclone performance.

关键词： Gas-solid cyclone Inlet particle spatial distribution Four-way coupling separation efficiency Scattered particle

High-efficiency magnetophoretic separation based on synergy of magnetic force field and flow field in microchannels

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Science China(Technological Sciences) 2011年第12期54卷 3311-3319页

作者： WU XinYu WU HuiYing HU DingHua School of Mechanical and Power Engineering Shanghai Jiao Tong University Shanghai 200240 China

Magnetophoresis is one of the most important separation methods in biological and chemical engineering. In this paper,a novel impact parameter on separation efficiency,i.e.,the angle between the vectors of magnetic force and fluid velocity,was derived from the basic equation describing the motion of magnetic beads in microchannels. It is proposed that one of the most important approaches for separation efficiency enhancement is to improve the coordination of magnetic force field and fluid flow field. A T-shaped microchannel magnetophoretic separator was designed based on the angle. And then a two-dimensional dynamic model of magnetic beads moving in microchannels was established to study the separation efficiency of T-shaped microseparator by combined use of finite element method and Runge-Kutta method. The results show that the capture effi-ciency of T-shaped microseparator is much higher than that of the straight microseparator at the same conditions. For small magnetic beads at high fluid velocities,the designed T-shaped microseparator could still keep high separation efficiency whereas the conventional straight microseparator fails to separate the magnetic beads. Further analysis shows that the mechanism of separation efficiency enhancement lies in the synergy of magnetic force field and flow field,which directly leads to large deflected velocity of the magnetic beads from the main stream,and thus increasing the separation efficiency. It is anticipated that the results in this paper are theoretically helpful for the optimum design of highly efficient magnetophoretic separators.

关键词： magnetophoretic separation T-shaped microchannel field synergy separation efficiency

separation of galena and chalcopyrite using the difference in their surface acid corrosion characteristics

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International Journal of Minerals,Metallurgy and Materials 2023年第11期30卷 2157-2168页

作者： Haiyun Xie Jialing Chen Pei Zhang Likun Gao Dianwen Liu Luzheng Chen Faculty of Land and Resources Engineering Kunming University of Science and TechnologyKunming 650093China Yunnan Key Laboratory of Green separation and Enrichment of Strategic Mineral Resources Kunming 650093China

Galena(PbS)and chalcopyrite(CuFeS_(2))are sulfide minerals that exhibit good floatability ***,efficiently separating them via common flotation is ***,a new method of surface sulfuric acid corrosion in conjunction with flotation separation was proposed,and the efficient separation of galena and chalcopyrite was successfully *** angle test results showed a substantial decrease in surface contact angle and a selective inhibition of surface floatability for corroded ***,the contact angle and floatability of corroded chalcopyrite remained almost *** electron microscope results confirmed that sulfuric acid corrosion led to the formation of a dense oxide layer on the galena surface,whereas the chalcopyrite surface remained unaltered.X-ray photoelectron spectroscopy results showed that the chemical state of S^(2-)on the surface of corroded galena was oxidized to SO_(4)^(2-).A layer of hydrophilic PbSO4was formed on the surface,leading to a sharp decrease in galena ***,new hydrophobic CuS_(2),CuS,and Cu_(1-x)Fe_(1-y)S_(2-z)species exhibiting good floatability were generated on the chalcopyrite ***,theoretical analysis results were further verified by corrosion–flotation separation *** galena–chalcopyrite mixture was completely separated via flotation separation under appropriate corrosion acidity,corrosion temperature,and corrosion time.A novel approach has been outlined in this study,providing potential applications in the efficient separation of refractory copper–lead sulfide ore.

关键词： surface acid corrosion galena chalcopyrite flotation separation efficiency

Analysis of the nutation and precession of the vortex core and the influence of operating parameters in a cyclone separator

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Chinese Journal of Chemical Engineering 2022年第6期35卷 1-10页

作者： Pan Zhang Guanghui Chen Weiwen Wang Guodong Zhang Huaming Wang College of Electromechanical Engineering and Key Laboratory of Multiphase Flow Reaction and separation Engineering of Shandong Province Qingdao University of Science and TechnologyQingdao 266069China College of Chemical Engineering Qingdao University of Science and TechnologyQingdao 266043China School of Naval Architecture and Electrical Engineering Zhejiang Ocean UniversityZhoushan 316022China

Vortices motion in the anisotropic turbulent flow of cyclones makes a vital impact on flow stability and collection ***,there remains a lack of clarity in the overall feature of vortices *** this work,a numerical analysis was conducted to clarify the complex motion of the vortex core in a cyclone *** validity of the numerical model was demonstrated by comparing the computational results with experimental data in the *** revealed by the results,the vortex core not only has a precession motion about the geometrical center axis but also does a nutation motion in the axial *** frequencies of the precession motions show two main *** the magnitudes of the precession and nutation motions have non-uniform distributions in the ***,the precession-nutation motions of the vortex cores exhibit a similar fluctuant pattern to the dust ring on the separator *** inlet gas velocity and the inlet solid loading show vital effects on the magnitudes and frequencies of precession and nutation motion.

关键词： Cyclone separator Precession vortex core Nutation motion separation efficiency Numerical simulation Fluid mechanics

A review of intelligent ore sorting technology and equipment development

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International Journal of Minerals,Metallurgy and Materials 2022年第9期29卷 1647-1655页

作者： Xianping Luo Kunzhong He Yan Zhang Pengyu He Yongbing Zhang Jiangxi Key Laboratory of High-efficiency Development and Application of Tungsten Resources Jiangxi University of Science and TechnologyGanzhou 341000China Jiangxi Key Laboratory of Mining&Metallurgy Environmental Pollution Control Jiangxi University of Science and TechnologyGanzhou 341000China Faculty of Resource and Environmental Engineering Jiangxi University of Science and TechnologyGanzhou 341000China

Under the background of increasingly scarce ore worldwide and increasingly fierce market competition,developing the mining industry could be strongly *** ore sorting equipment not only improves ore use and enhances the economic benefits of enterprises but also increases the ore grade and lessens the grinding cost and tailings ***,long-term research on intelligent ore sorting equipment found that the factors affecting sorting efficiency mainly include ore information identification technology,equipment sorting actuator,and information processing *** high precision,strong anti-interference capability,and high speed of these factors guarantee the separation efficiency of intelligent ore sorting *** ore sorter,X-ray ore transmission sorter,dual-energy X-ray transmission ore sorter,X-ray fluorescence ore sorter,and near-infrared ore sorter have been successfully developed in accordance with the different characteristics of minerals while ensuring the accuracy of equipment sorting and improving the equipment sorting *** the continuous improvement of mine automation level,the application of online element rapid analysis technology with high speed,high precision,and strong anti-interference capability in intelligent ore sorting equipment will become an inevitable trend of equipment development in the ***-induced breakdown spectroscopy,transientγneutron activation analysis,online Fourier transform infrared spectroscopy,and nuclear magnetic resonance techniques will promote the development of ore sorting *** addition,the improvement and joint application of additional high-speed and high-precision operation algorithms(such as peak area,principal component analysis,artificial neural network,partial least squares,and Monte Carlo library least squares methods)are an essential part of the development of intelligent ore sorting equipment in the future.

关键词： intelligent ore sorting technology sorting equipment separation efficiency online element rapid analysis technology

Effects of the properties of FCCS on the removing of catalyst particles from FCCS under a DC electrostatic field

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Petroleum Science 2023年第3期20卷 1885-1894页

作者： Qiang Li Qing-Zhu Qiu Hao Cao Hui-Zhen Yang Wei-Wei Xu Zhao-Zeng Liu College of New Energy China University of Petroleum(East China)QingdaoShandong 266580China

Catalytic cracking is the main method to lighten heavy crude oil,this process can produce high quality oil products such as gasoline and diesel,but also produces a large amount of fluid catalytic cracking slurry(FCCS).The catalyst particles in FCCS seriously restrict the secondary processing of FCCS and need to be removed,and the properties of Fccs is an important factor that affects the removal efficiency of the catalyst *** on the"effective contact point"model proposed by the research group,this study further proposed the"electrostatic separation efficiency calculation"*** this model,since Fccs has a uniform distribution of catalyst particles,the ratio of the number of catalyst particles can be expressed as the ratio of area to achieve the calculation of separation *** the catalyst removal efficiency under different viscosity was analyzed,thus verifying the feasibility of this *** effects of temperature and mass ratio of four components on the viscosity of FccS were investigated respectively,then the effects of temperature and four components'mass ratio on the electrostatic sep-aration can be directly converted into the effect of viscosity on the electrostatic separation *** the results show the electrostatic separation efficiency decreases with increasing viscosity,and the best separationtemperatureis120℃.

关键词： Fluid catalytic cracking slurry(FCCS) separation efficiency Viscosity Temperature Four components'mass ratio

Characteristic research of regeneration process of particulate filter medium in vibrated fluidized bed

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Clean Energy 2023年第6期7卷 1189-1198页

作者： Bing Liu Lixin He Xianglong Zhao Yi Guo Clean Coal Technology Center National Institute of Clean-and-Low-Carbon EnergyChina Energy GroupFuture Science CityChangping DistrictBeijing 102211P.R.China

The vibrational fluidized bed is innovatively adopted to regenerate the particulate filter medium for the purification of crude syn-thesis gas from the coal gasification *** research of vibrated fluidized beds during dust-containing particulate filter medium regeneration has been carried *** ideal transport model of particulate filter medium on the distributor is estab-lished and verified by using *** mean residence time of the particulate filter medium can be reduced by 72%from 5.5 to 1.5 min with an increase in the working frequency from 50 to 60 *** thickness of the bed layer is linearly increased with the feeding rate of the particulate filter medium under ideal working *** resistance models of the fluidizing air are built up and validated,and they can be used to calculate the pressure drop of the static bed layer of the particulate filter medium on the flu-idizing air distributor,which is the maximum value of the dynamic bed layer with the same *** fluidizing air makes the mean residence time of the particulate filter medium decrease by 50%and reduces the difference in the particulate mean residence time under different feeding-rate *** regeneration effect of dust-containing filter medium particles in a vibrated fluidized bed is *** air with superficial velocity ranging from 0 to 0.6~0.9 m·s-1 makes the regeneration efficiency increase from 29.41%to 70.59~88.24%.This article provides a reference for the industrial application of a vibrated fluidized bed for the par-ticulate filter medium recycling system.

关键词： vibrated fluidized bed filter medium residence time pressure drop separation efficiency coal gasification

separation of Silver Nanocrystals for Surface-enhanced Raman Scattering Using Density Gradient Centrifugation

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Journal of Materials Science & Technology 2015年第8期31卷 834-839页

作者： Qijin Huang Wenfeng Shen Ruiqin Tan Wei Xu Weijie Song Ningbo Institute of Material Technology and Engineering Chinese Academy of Sciences Faculty of Information Science and Engineering Ningbo University

One-dimensional silver nanocrystals （AgNCs） have been prepared by a polyol process using sodium hydroxide and nitric acid at a constant silver source concentration. Results indicate that the acidity- basicity plays an important role in silver-nanocrystal formation. Different morphologies of AgNCs were synthesized by changing the NaOH or HNO3 amount. We demonstrate that nearly monodisperse silver nanocrystals can be separated from polydisperse samples using density gradient centrifugation separation （DGCS）. We also demonstrate that the separated AgNCs can be used as substrates for surface- enhanced Raman scattering （SERS） spectroscopy. The separation approach provides a method of improving the nanocrystal quality produced by large-scale synthetic methods.

关键词： Silver Raman scattering Nanomaterials separation efficiency