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Computational study of bubble coalescence/break-up behaviors and bubble size distribution in a 3-D pressurized bubbling gas-solid fluidized bed of Geldart A particles

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Chinese Journal of Chemical Engineering 2022年第4期35卷 485-496页

作者： Teng Wang Zihong Xia Caixia Chen Department of Energy and Chemical Engineering East China University of Science and TechnologyShanghai 200237China

A computational study was carried out on bubble dynamic behaviors and bubble size distributions in a pressurized lab-scale gas-solid fluidized bed of Geldart A particles.High-resolution 3-D numerical simulations were performed using the two-fluid model based on the kinetic theory of granular flow.A finegrid,which is in the range of 3–4 particle diameters,was utilized in order to capture bubble structures explicitly without breaking down the continuum assumption for the solid phase.A novel bubble tracking scheme was developed in combination with a 3-D detection and tracking algorithm(MS3 DATA)and applied to detect the bubble statistics,such as bubble size,location in each time frame and relative position between two adjacent time frames,from numerical simulations.The spatial coordinates and corresponding void fraction data were sampled at 100 Hz for data analyzing.The bubble coalescence/break-up frequencies and the daughter bubble size distribution were evaluated by using the new bubble tracking algorithm.The results showed that the bubble size distributed non-uniformly over cross-sections in the bed.The equilibrium bubble diameter due to bubble break-up and coalescence dynamics can be obtained,and the bubble rise velocity follows Davidson’s correlation closely.Good agreements were obtained between the computed results and that predicted by using the bubble break-up model proposed in our previous work.The computational bubble tracking method showed the potential of analyzing bubble motions and the coalescence and break-up characteristics based on time series data sets of void fraction maps obtained numerically and experimentally.

关键词： Pressurized gas-solid bubbling fluidized bed Geldart A particles Bubble size distribution Coalescence break-up Bubble tracking algorithm

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Oxide transformation and break-up of liquid metal in boiling solutions

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Science China(Technological Sciences) 2020年第2期63卷 289-296页

作者： YANG LiXiang ZHAO Xi XU Shuo LU YongYu CHANG Hao LIU Jing Beijing Key Laboratory of Cryo-Biomedical Engineering and Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100039China Department of Biomedical Engineering School of MedicineTsinghua UniversityBeijing 100084China

The non-toxic gallium-based liquid metals(LMs) are promising for various newly emerging areas due to having excellent fluidity, high electrical and heat conductivity. However, the oxide layers often affect their applications. In this paper, we disclosed a straightforward boiling strategy to efficiently remove the oxide of LM in deionized water. Meanwhile such method was also demonstrated to be capable of quickly breaking up LM into droplets(mean 0.51 mm, SD 0.20 mm) in Na Cl solution,which has important value for manufacture purpose. According to the force analysis, surface tension of LM dominates the interaction between solution bubbles and LM under the same heating conditions. Then we characterized the surface morphology and compositions of LM droplets boiled(LMDB) using scanning electron microscope(SEM), X-ray diffraction(XRD) and Xray photoelectron spectroscopy(XPS) and tested the dynamic force between a rod and LMDB. It was shown that after being boiled in water, most of Ga2O3 was transformed to scattered α-Ga OOH nanorods which has less restriction to the deformation of LM and large resistance force(0.8 mN) was tested;otherwise, after boiled in Na Cl solution, more Ga2 O3 with contact patch structure reduces the surface resistance of LM(0.2 m N) and makes it to be broken up by bubbles. The different surface products are determined by the inhibition of hydrolysis of Ga3+by Na Cl solution. This study paved a simple way for oxide removal in neutral solution and mass production of LMD. It also suggests an efficient approach for exploring mechanisms of interactions between LM and bubbles, which is difficult to study otherwise in sonication.

关键词： liquid metal boiling solutions oxide transformation break-up hydrolysis inhibition

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break-up Process of Perturbed Molten Metal Jet and Preparation of Lead-Free Solder Balls

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Journal of Rare Earths 2004年第Z2期22卷 174-177页

作者： He Lijun Zhang Shuguang Zhang Shaoming Xu Jun Shi Likai National Engineering Research Center for Non-Ferrous Metals Composites General Research Institute for Non-Ferrous MetalsBeijing 100088China National Engineering Research Center for Non-Ferrous Metals CompositesGeneral Research Institute for Non-Ferrous MetalsBeijing 100088China National Engineering Research Center for Non-Ferrous Metals CompositesGeneral Research Institute for Non-Ferrous MetalsBeijing 100088China National Engineering Research Center for Non-Ferrous Metals CompositesGeneral Research Institute for Non-Ferrous MetalsBeijing 100088China National Engineering Research Center for Non-Ferrous Metals CompositesGeneral Research Institute for Non-Ferrous MetalsBeijing 100088China

Solder balls, which are used in advanced electronics packages such as BGA (Ball Grid Array) and CSP (Chip Scale Package) to substitute the leads and realize the electrical and mechanical connections between substrate and chip,have severe specifications in diameter tolerance, roundness and surface quality, and therefore challenge the traditional technologies for fabrication of metallic particles and powders. The present work made a survey of perturbed molten metal jet break-up process, observed the formation and growth of capillary wave of tin-lead melt jet by way of rapid solidification, and on the basis of the above research, successfully obtained tin-lead eutectic and Sn-4.0Ag-0.5Cu lead free solder balls with tight distribution and good sphericity of particles through optimization of processing parameters, forming a solid base for cost effectively producing solder balls.

关键词： solder balls jet break-up capillary wave perturbation

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Impact of gas pressure on particle feature in Fe-based amorphous alloy powders via gas atomization:Simulation and experiment

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Journal of Materials Science & Technology 2022年第10期105卷 203-213页

作者： Yutong Shi Weiyan Lu Wenhai Sun Suode Zhang Baijun Yang Jianqiang Wang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

Gas atomization is now an important production technique for Fe-based amorphous alloy powders used in additive manufacturing,particularly selective laser melting,fabricating large-sized Fe-based bulk metallic glasses.Using the realizable k-εmodel and discrete phase model theory,the flow dynamics of the gas phase and gas-melt two-phase flow felds in the close-wake condition were investigated to establish the correlation between high gas pressure and powder particle characteristics.The locations of the recirculation zones and the shapes of Mach disks were analyzed in detail for the type of discrete-jet closed-coupled gas atomization nozzle.In the gas-phase flow feld,the vortexes,closed to the Mach disk,are found to be a new deceleration method.In the two-phase flow feld,the shape of Mach disk changes from“S”-shape to“Z”-shape under the impact of the droplet flow.As predicted by the wave model,with the elevation of gas pressure,the size of the particle is found to gradually decrease and its distribution becomes more concentrated.Simulation results were compliant with the Fe-based amorphous alloy powder preparation tests.This study deepens the understanding of the gas pressure impacting particle features via gas atomization,and contributes to technological applications.

关键词： Gas atomization Fe-based amorphous powder Closed-wake Gas-melt flow break-up Particle size distribution

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Effect of Projectile break-up Threshold Energy on Incomplete Fusion at Energy ≈ 4 - 7 MeV/Nucleon

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Journal of Modern Physics 2014年第18期5卷 2063-2074页

作者： Sabir Ali Tauseef Ahmad Kamal Kumar Isar Ahmad Rizvi Avinash Agarwal Sandeep S. Ghugre Ajit Kumar Sinha Ashok Kumar Chaubey Department of Physics Aligarh Muslim University Aligarh India Department of Physics Bareilly College Bareilly India UGC-DAE Consortium for Scientific Research Kolkata India Department of Physics Addis Ababa University Addis Ababa Ethiopia

Complete and incomplete fusion cross sections have been measured for the 20Ne + 51V system to investigate the influence of projectile break-up at or above the barrier energies. The excitation function of the individual reaction channel measured using off-line γ-ray spectroscopy has been compared with those estimated theoretically using the statistical model code PACE4. A significant fraction of incomplete fusion has been found in the production of residues involving α-particle in the exit channel. In order to understand the energy dependence of incomplete fusion reactions, incomplete fusion fraction has been deduced, which has also been compared with the earlier data available for 12C and 16O projectiles to look for the projectile structure dependence.

关键词： Heavy Ion Induced Reaction Complete Fusion Incomplete Fusion break-up Reaction

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Model Calculation of n + 6Li Reactions Below 20 MeV

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Communications in Theoretical Physics 2001年第10期36卷 437-442页

作者： ZHANG Jing-Shang HAN Yin-Lu China Nuclear Data Center China Institute of Atomic Energy Beijing 102413 China China Nuclear Data Center China Institute of Atomic Energy Beijing 102413 China

Based on the unified Hauser-Feshbach and exciton model for light nuclei, the calculations of reaction cross sections and the double-differential cross sections for n + 6Li are performed. Since all of the first-particle emissions are from the compound nucleus to the discrete levels, the angular momentum coupling effect in pre-equilibrium mechanism must be taken into account. The fitting of the measured data indicates that the three-body break-up process needs to be involved, and the pre-equilibrium reaction mechanism dominates the reaction processes. In light nucleus reactions the recoil effect must be taken into account.

关键词： pre-equilibrium emission, discrete levels, three-body break-up process

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Geochemistry, Sr-Nd-Pb Isotopic Compositions and Zircon U-Pb Geochronology of Neoproterozoic Mafic Dyke in the Douling Complex, South Qinling Belt, China

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Journal of Earth Science 2020年第2期31卷 237-248页

作者： Tong Li Liang Liu Xiao-Ying Liao Yong-Sheng Gai Tuo Ma Chao Wang State Key Laboratory of Continental Dynamics Department of GeologyNorthwest UniversityXi'an 710069China

Mafic dyke swarm is widely developed in Proterozoic continental lithosphere.The Gangou diabase dyke from the Xixia area,intruded into the Douling complex of the South Qinling belt,yields zircon upb age of 731 Ma.It has low SiO2 content(49.02 wt.%-49.37 wt.%)and Mg^#(34.0–37.7)and shows characteristics of subalkaline tholeiite series.They show highΣREE(155.5×10^-6–184.7×10^-6),weak negative Eu anomaly(δEu=0.88-0.93),slight depletion of Nb and Ta,and enrichment of LILE.Their major and trace element,Sr-Nd-Pb isotope and clinopyroxene compositions indicate that it originated from the partial melting of the asthenospheric mantle within-plate extension setting and was slightly contaminated by crust compositions.The similarities of formation age,petrogenesis,source characteristic and tectonic setting for Gangou diabase with mafic dykes in Wudang Block and mafic volcanic rocks in Yaolinghe Group indicate that the South Qinling belt underwent strong continental extension in Neoproterozoic during 796–685 Ma most likely correspondence to the breaking-up of the Rodinia supercontinent.

关键词： Douling complex diabase dyke LA-ICP-MS zircon U-Pb dating Sr-Nd-Pb isotope Rodinia supercontinent break-up

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2000-2016年青海湖湖冰物候特征变化（英文）

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Journal of Geographical Sciences 2019年第1期29卷 115-130页

作者：祁苗苗姚晓军李晓锋段红玉高永鹏刘娟 College of Geography and Environment Sciences Northwest Normal University

Lake ice phenology is considered a sensitive indicator of regional climate change. We utilized time series information of this kind extracted from a series of multi-source remote sensing(RS) datasets including the MOD09 GQ surface reflectance product, Landsat TM/ETM_+ images, and meteorological records to analyze spatiotemporal variations of ice phenology of Qinghai Lake between 2000 and 2016 applying both RS and GIS technology. We also identified the climatic factors that have influenced lake ice phenology over time and draw a number of conclusions. First, data show that freeze-up start(FUS), freeze-up end(FUE), break-up start(BUS), and break-up end(BUE) on Qinghai Lake usually occurred in mid-December, early January, mid-to-late March, and early April, respectively. The average freezing duration(FD, between FUE and BUE), complete freezing duration(CFD, between FUE and BUS), ice coverage duration(ICD, between FUS and BUE), and ablation duration(AD, between BUS and BUE) were 88 days, 77 days, 108 days and 10 days, respectively. Second, while the results of this analysis reveal considerable differences in ice phenology on Qinghai Lake between 2000 and 2016, there has been relatively little variation in FUS times. Data show that FUE dates had also tended to fluctuate over time, initially advancing and then being delayed, while the opposite was the case for BUS dates as these advanced between 2012 and 2016. Overall, there was a shortening trend of Qinghai Lake's FD in two periods, 2000–2005 and 2010–2016, which was shorter than those seen on other lakes within the hinterland of the Tibetan Plateau. Third, Qinghai Lake can be characterized by similar spatial patterns in both freeze-up(FU) and break-up(BU) processes, as parts of the surface which freeze earlier also start to melt first, distinctly different from some other lakes on the Tibetan Plateau. A further feature of Qinghai Lake ice phenology is that FU duration(between 18 days and 31 days) is about 10 days longer than BU duration(between 7 days and 20 days). F

关键词： lake ice phenology freeze-up and break-up MODIS Qinghai Lake

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Numerical simulation on dynamic behaviors of bubbles flowing through bifurcate T-junction in microfluidic device

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Chinese Physics B 2019年第10期28卷 417-427页

作者：吴梁玉刘凌波韩笑天李倩文杨卫波 School of Hydraulic Energyand Power EngineeringYangzhou UniversityYangzhou 225127China Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and EnvironmentSoutheast UniversityNanjing 210096China

Based on the volume of fluid(VOF) method, a numerical model of bubbles splitting in a microfluidic device with T-junction is developed and solved numerically. Various flow patterns are distinguished and the effects of bubble length,capillary number, and diameter ratio between the mother channel and branch are discussed. The break-up mechanism is explored in particular. The results indicate that the behaviors of the bubbles can be classified into two categories: break-up and non-break. Under the condition of slug flowing, the branches are obstructed by the bubbles that the pressure difference drives the bubbles into break-up state, while the bubbles that retain non-break state flow into an arbitrary branch under bubbling flow condition. The break-up of the short bubbles only occurs when the viscous force from the continuous phase overcomes the interfacial tension. The behavior of the bubbles transits from non-break to break-up with the increase of capillary number. In addition, the increasing of the diameter ratio is beneficial to the symmetrical break-up of the bubbles.

关键词： microfluidic T-junction bubble break-up numerical simulation

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Plate tectonic setting and genetic types of gas (oil)-bearing basins in China

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Science China Earth Sciences 1997年第1期40卷 16-22页

作者：张一伟陈发景陆克政漆家福 Department of Earth Sciences University of Petroleum Beijing 102200 China Department of Geology and Energy Resources China University of Geosciences Beijing 100083 China)

The plate tectonic setting and genetic types of the gas (oil)-bearing basins in China are studied. Based on the history of break-up and amalgamation of Pangea, the three tectonic evolutionary megastages can be divided and the sedimentary basins in China are classified as Palaeozoic and Meso-Cenozoic basins. The Palaeozoic gas(oil)-bearing basins are mainly located in intracratonic basins, on which different types of Meso-Cenozoic basins are superimposed, and located in cratonic marginal basins and aulacogens destroyed with a slight degree, (n contrast, the Mesozoic and Cenozoic gas (oil)-bearing basins mainly formed in extensional foreland and intracontmental shortening flexural basins.

关键词： plate tectonic setting break-up and amalgamation of Pangea Palaeozoic basins Mesozoic and Cenozoic basins gas-bearing basins

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