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Modeling of Coalescence and Separation of Liquid Droplets During Solidification of Immiscible Alloys
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作者 Lirong Tong Nagy El-Kaddah 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期101-,共1页
Directional solidification methods are being used f or in-situ production of metallic immiscible composites. A quantitative understa nding of the dynamic behavior and growth kinetics of the nucleated second phase duri... Directional solidification methods are being used f or in-situ production of metallic immiscible composites. A quantitative understa nding of the dynamic behavior and growth kinetics of the nucleated second phase during solidification is necessary to produce homogeneous dispersion in solidifi ed composites. This paper presents a mathematical model for describing the grow th of nucleated dispersed phase in the two-liquid phase region ahead of the sol idification front and the entrapment of these droplets by the moving solid-liqu id interface in vertical unidirectional solidification systems. The model has t wo components. A macro-heat transfer model for describing the temperature prof iles and the rate of advance of the solidification front. The dynamic behavior and coalescence and growth of nucleated droplets in the two-liquid phase region under the influence of effective gravity and thermocapillary forces were repres ented through the solution the droplet momentum and mass conservation equations in particle space. These two components of the models were coupled through a sp ecial algorithm for tracking the particle location and size with respect to movi ng solidification front in the solidification time scale. The model is used to study the particle size distribution in unidirectional solidified Zn-Bi hypermo notectic alloys at reduced gravity conditions. It has been found that the parti cle size and distribution in the solidified alloy depends on solidification rate and the ratio of effective gravity to thermocapillary forces. It was also foun d that uniform dispersion could only be obtained in a very narrow range of effec tive gravity values near zero gravity. The model predictions were compared agai nst experimental measurements obtained at different effective gravity conditions in a novel unidirectional solidification apparatus that uses electromagnetic fo rces to modulate gravitational forces. The model was found to reasonably predic t the experimentally measured particle size and distribution over the entire ran ge of effective gravity investigated as well as gravity conditions for settling and flotation of the second phase during solidification. The practical signific ance of these findings will be discussed. 展开更多
关键词 Modeling of Coalescence and Separation of liquid droplets During Solidification of Immiscible Alloys
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Axisymmetric wetting of a liquid droplet on a stretched elastic membrane
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作者 C.Q.RU 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第6期997-1006,共10页
Wetting of a liquid droplet on another liquid substrate is governed by the well-known Neumann equations.The present work aims to develop an explicit modified version of the Neumann equations for axisymmetric wetting o... Wetting of a liquid droplet on another liquid substrate is governed by the well-known Neumann equations.The present work aims to develop an explicit modified version of the Neumann equations for axisymmetric wetting of a liquid droplet on a highly stretched elastic membrane of non-zero bending rigidity.An explicit modified form of the Neumann equations is derived to determine the two contact angles,which is reduced to Young's equation for a liquid droplet on a rigid membrane or to the Neumann equations for a liquid droplet on another liquid substrate.Further implications of the modified Neumann equations are examined by comparison with some previous results reported in the recent literature,particularly considering the ranges of material and geometrical parameters of the liquid droplet-membrane system which have not been recently addressed in the literature. 展开更多
关键词 Neumann equation Young's equation liquid droplet membrane PRETENSION
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BREAK-UP MECHANISM OF METAL DROPLETS GENERATED BY AN ELECTROHYDRODYNAMIC TECHNIQUE 被引量:1
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作者 X.F. Yu Z.Q. Hu +1 位作者 H.S. Hu Z Jiang and X. Liu(State Key Laboratory of RSA, Institote of Metal Research, Chinese Academy of Sciences, Shenyang110015, China)(Northeastern University Shenyang 110006, China) 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1997年第1期39-45,共7页
Nanometer powders can be produced by an electrohydrodynamic technique. The breakup mechanism of the metal droplets generated by the electrohydrodynamic technique was analysed. It showed that the applied voltage, the e... Nanometer powders can be produced by an electrohydrodynamic technique. The breakup mechanism of the metal droplets generated by the electrohydrodynamic technique was analysed. It showed that the applied voltage, the electric field Btrength, the properties of the molten metal and the volumetric flow rate of the molten metal directly effect the breat-up extent of the metal droplets. 展开更多
关键词 electrohydrodynamic technique nanometer powden charged liquid droplet surface charge density
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Pre-concentration and determination of amitriptyline residues in waste water by ionic liquid based immersed droplet microextraction and HPLC 被引量:1
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作者 M.T.Hamed Mosavian Z.Es’haghi +1 位作者 N.Razavi S.Banihashemi 《Journal of Pharmaceutical Analysis》 SCIE CAS 2012年第5期361-365,共5页
This paper describes a new approach for the determination of amitriptyline in wastewater by ionic liquid based immersed droplet microextraction (IL-IDME) prior to highperformance liquid chromatography with ultraviol... This paper describes a new approach for the determination of amitriptyline in wastewater by ionic liquid based immersed droplet microextraction (IL-IDME) prior to highperformance liquid chromatography with ultraviolet detection. 1-Hexyl-3-methylimidazolium hexafluorophosphate ([C6MIM][PF6]) was used as an ionic liquid. Various factors that affect extraction, such as volume of ionic liquid, stirring rate, extraction time, pH of the aqueous solution and salting effect, were optimized. The optimal conditions were as follows: microextraction time, 10 min; stirring rate, 720 rpm; pH, 11; ionic drop volume, 100 uL; and no sodium chloride addition. In quantitative experiments the method showed linearity in a range from 0.01 to 10 ug/mL, a limit of detection of 0.004 ug/mL and an excellent pre-concentration factor (PF) of 1100. Finally, the method was successfully applied to the determination of amitriptyline in the hospital wastewater samples. 展开更多
关键词 Antidepressant Ionic liquid based immersed droplet microextraction (IL-IDME) High performance liquid chromatography(HPLC)
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Study on Nonlinear Coupling Wave Model for Liquid Droplet-Solid Impact
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作者 张荻 谢永慧 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2002年第4期222-227,共6页
In order to investigate the material corrosion by liquid droplet solid impact, a nonlinear coupling wave model adopted to analyze the impact between the spherical liquid droplet and an elastic solid plane has been dev... In order to investigate the material corrosion by liquid droplet solid impact, a nonlinear coupling wave model adopted to analyze the impact between the spherical liquid droplet and an elastic solid plane has been developed. Many usable results such as the dimensionless pressure in the contact plane of liquid solid and inside the liquid droplet, the equivalent stress distribution inside the solid, the effect of solid elasticity on the impact, and the locations of the maximum equivalent stress in different... 展开更多
关键词 numerical analysis CORROSION liquid droplet solid impact NONLINEARITY WAVE
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Millimeter-Scale Liquid Droplet Migration on Solid Surface with Temperature Gradient: A Simulation Investigation
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作者 Zheng Jingyuan 《Modern Mechanical Engineering》 2020年第3期34-38,共5页
In this pap</span><span style="font-family:Verdana;">er, we established a time-dependent model that inv</span><span style="font-family:Verdana;">estigate</span></sp... In this pap</span><span style="font-family:Verdana;">er, we established a time-dependent model that inv</span><span style="font-family:Verdana;">estigate</span></span><span style="font-family:Verdana;">s</span><span style="font-family:""><span style="font-family:Verdana;"> the migrati</span><span style="font-family:Verdana;">on behavior of a millimeter-scale liquid droplet on a solid surfa</span><span style="font-family:Verdana;">ce with tem</span><span style="font-family:Verdana;">perature gradient. Both fluid mechanics and heat trans</span><span style="font-family:Verdana;">fer are incorporated in the model. The Navier-Stokes equation is employed both inside and outside the droplet. Size variation is observed in the transient simulation. Results show that the velocity of the migration is about 1.7 mm/s under a temperature gradient of 30 K/mm. The model is consistent with results with previous literatures. 展开更多
关键词 liquid Droplet Fluid Mechanics Navier-Stokes Equation
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Microstructure evolution of hot pressed AZ91D alloy chips reheated to semi-solid state
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作者 许红雨 吉泽升 +1 位作者 胡茂良 王振宇 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第12期2906-2912,共7页
AZ91D magnesium alloy chips, which were directly collected on the spot of machining process, were recycled to prepare billet via hot pressing for semi-solid processing. The semi-solid microstructure evolution of the b... AZ91D magnesium alloy chips, which were directly collected on the spot of machining process, were recycled to prepare billet via hot pressing for semi-solid processing. The semi-solid microstructure evolution of the billet during reheating was investigated. The results indicate that there are three stages during reheating to semi-solid state: the dissolution of Mg17Al12 and diffusion of Al into α-Mg matrix, the melting of the region with high content of solute and formation of isolated solid particles, and spheroidization and growth of solid particles. Meanwhile, a number of entrapped liquid droplets form within solid particles. In addition, the number and size of entrapped liquid droplets rely on the holding time in the semi-solid temperature range. With increasing isothermal holding time, the solid fraction remains unchanged when the solid-liquid system reaches the dynamic equilibrium at last, while the solid particles become more globular and the average size of solid particles increases owing to the decreasing of interfacial energy and the effect of interfacial tension. 展开更多
关键词 AZ91D alloy CHIPS semi-solid microstructure microstructure evolution RECYCLING entrapped liquid droplet interfacial energy interfacial tension
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Unraveling the morphological evolution mechanism of solid sulfur species in lithium-sulfur batteries with operando light microscopy 被引量:1
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作者 Jingqiang Zheng Chaohong Guan +7 位作者 Huangxu Li Yangyang Xie Junxian Hu Kai Zhang Bo Hong Yanqing Lai Jie Li Zhian Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第10期460-468,I0012,共10页
Solid-liquid phase conversion between various sulfur species in lithium-sulfur(Li-S)batteries is a fundamental reaction of the sulfur cathode.Disclosing the morphological evolution of solid sulfur species upon cycling... Solid-liquid phase conversion between various sulfur species in lithium-sulfur(Li-S)batteries is a fundamental reaction of the sulfur cathode.Disclosing the morphological evolution of solid sulfur species upon cycling is of great significance to achieving high energy densities.However,an in-depth investigation of the internal reaction is still lacking.In this work,the evolution process of solid sulfur species on carbon substrates is systematically studied by using an operando light microscope combined with in situ electrochemical impedance spectra technology.The observation of phenomena such as bulk solid sulfur species can form and dissolve independently of the conductive substrates and the transformation of supercooled liquid sulfur to crystalline sulfur.Based on the phenomena mentioned above,a possible mechanism was proposed in which the dissolution reaction of solid sulfur species is a spatially free reaction that involves isotropic physical dissolution,diffusion of molecules,and finally the electrochemical reaction.Correspondingly,the formation of solid sulfur species tends to be a form of crystallization in a saturated solution rather than electrodeposition,as is commonly believed.Our findings offer new insights into the reaction of sulfur cathodes and provide new opportunities to design advanced sulfur cathodes for Li-S batteries. 展开更多
关键词 Lithium-sulfur batteries Morphological evolution Supercooled liquid sulfur Operando light microscopy liquid sulfur droplets
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Analysis of Material Loss Behavior According to Long-Term Experiments on LDIE-FAC Multiple Degradation of Carbon Steel Materials 被引量:1
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作者 Kyeong Mo Hwang Dong Jin Lee +2 位作者 Hun Yun Seung Chang Yoo Ji Hyeon Kim 《World Journal of Nuclear Science and Technology》 2022年第1期1-10,共10页
Recently, damage caused by liquid droplet impingement erosion (LDIE) in addition to flow-accelerated corrosion (FAC) has frequently occurred in the secondary side steam piping of nuclear power plants, and the damage-o... Recently, damage caused by liquid droplet impingement erosion (LDIE) in addition to flow-accelerated corrosion (FAC) has frequently occurred in the secondary side steam piping of nuclear power plants, and the damage-occurring frequency is expected to increase as their operating years’ increase. In order to scrutinize its causes, therefore, an experimental study was conducted to understand how the behavior of LDIE-FAC multiple degradation changes when the piping of nuclear power plants is operated for a long time. Experimental results show that more magnetite was formed on the surface of the carbon steel specimen than on the low-alloy steel specimen, and that the rate of magnetite formation and extinction reached equilibrium due to the complex action of liquid droplet impingement erosion and flow-accelerated corrosion after a certain period of time. Furthermore, it was confirmed at the beginning of the experiment that A106 Gr.B specimen has more mass loss than A335 P22 specimen. After a certain period of time, however, the mass loss tends to be the opposite. This is presumed to have resulted from the magnetite formed on the surface playing a role in suppressing liquid droplet impingement erosion. In addition, it was confirmed that the amount of erosion linearly increases under the conditions in which the formation and extinction of magnetite reach equilibrium. 展开更多
关键词 liquid Droplet Impingement Erosion (LDIE) Flow-Accelerated Corrosion (FAC) Multiple Degradations ToSPACE Wall Thinning MAGNETITE
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Hard-magnetic liquid metal droplets with excellent magnetic field dependent mobility and elasticity
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作者 Xiaokang He Mingyang Ni +2 位作者 Jianpeng Wu Shouhu Xuan Xinglong Gong 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2021年第33期60-68,共9页
Magnetic liquid metal droplets(MLMDs)have been proven to be very important in many fields such as flexible electronics and soft robotics.Usually,soft magnetic particles such as nickel(Ni)and iron(Fe)are mixed or suspe... Magnetic liquid metal droplets(MLMDs)have been proven to be very important in many fields such as flexible electronics and soft robotics.Usually,soft magnetic particles such as nickel(Ni)and iron(Fe)are mixed or suspended into the liquid metal to obtain soft MLMDs(S-LMDs),which can be easily manipulated under the magnetic field due to the favorable deformability and flexibility.In addition,hard magnetic particles such as neodymium iron boron(Nd Fe B)with a high residual magnetization can also be dispersed into the liquid metal and the hard MLMDs(H-LMDs)become more compact due to the interaction between internal particles induced by remanence.This work reports a kind of H-LMDs with high surface tension,high flexibility and mechanical robustness,whose electrical conductivity and strength are better than the S-LMDs.Under the magnetic field,the H-LMDs have a faster response time(0.58 s)and a larger actuating velocity(4.45 cm/s)than the S-LMDs.Moreover,the H-LMDs show excellent magnetic controllability,good elasticity and favorable mobility,as demonstrated by magnetically actuated locomotion,bounce tests and rolling angle measurements.Finally,the droplets can be further applied in wheeldriven motors and micro-valve switches,which demonstrates their high application potential in robotic manipulation and microfluidic devices. 展开更多
关键词 Magnetic liquid metal droplets NdFeB particles Magnetic controllability Micro-valve
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TRACKING METHODS FOR FREE SURFACE AND SIMULATION OF A LIQUID DROPLET IMPACTING ON A SOLID SURFACE BASED ON SPH 被引量:4
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作者 LI Da-ming XU Ya-nan +2 位作者 LI Ling-ling LU Hui-jiao BAI Ling 《Journal of Hydrodynamics》 SCIE EI CSCD 2011年第4期447-456,共10页
With some popular tracking methods for free surface, simulations of several typical examples are carried out under various flow field conditions. The results show that the Smoothed Particle Hydrodynamics (SPH) metho... With some popular tracking methods for free surface, simulations of several typical examples are carried out under various flow field conditions. The results show that the Smoothed Particle Hydrodynamics (SPH) method is very suitable in simulating the flow problems with a free surface. A viscous liquid droplet with an initial velocity impacting on a solid surface is simulated based on the SPH method, and the surface tension is considered by searching the free surface particles, the initial impact effect is considered by using the artificial viscosity method, boundary virtual particles and image virtual particles are introduced to deal with the boundary problem, and the boundary defect can be identified quite well. The comparisons of simulated results and experimental photographs show that the SPH method can not only exactly simulate the spreading process and the rebound process of a liquid droplet impacting on a solid surface but also accurately track the free surface particles, simulate the free-surface flow and determine the shape of the free surface due to its particle nature. 展开更多
关键词 Smoothed Particle Hydrodynamics (SPH) method viscous liquid droplet impacting on a solid surface free surface
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Simulation of two-phase plume field of liquid thruster 被引量:2
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作者 HE XiaoYing HE BiJiao CAI GuoBiao 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第6期1739-1748,共10页
When the liquid propellant thruster works,its plume field would contain many propellant liquid droplets,especially at pulse state.Liquid droplets may move along with the gas flow and deposit on the components of space... When the liquid propellant thruster works,its plume field would contain many propellant liquid droplets,especially at pulse state.Liquid droplets may move along with the gas flow and deposit on the components of spacecraft as contamination.The simulation of the plume field involving the gas molecules and liquid droplets is an important part in contamination studies of thruster plume.Based on the PWS software developed by Beihang University(BUAA),axial-symmetric two-phase direct simulation Monte Carlo(DSMC) method is used with the liquid droplet taken as a kind of solid particle.The computation of gas-to-particle effect and gas reflection on the particle surface are decoupled.The inter-particle collision is also considered.The gas parameters at nozzle exit of 120N engine after 20 ms pulse work are taken as the entrance condition of the numerical simulation.Four test cases are conducted for comparison of different collision modules.Simulation results show that the effects of liquid propellant droplets mainly concentrate near the axis line of engine.The particle-to-gas collision would cause evident differences in the gas field and subtle differences in the particle phase.The liquid droplets in the plume field are generally accelerated and convected by the gas molecules.The DSMC method is proved to be a feasible solver to numerically simulate the two-phase flow involving solid phase and rarefied gas flow. 展开更多
关键词 two-phase plume field DSMC liquid droplet liquid thruster pulse
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A Review on Thermal Design of Liquid Droplet Radiator System 被引量:1
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作者 CHONG Daotong ZHU Maoguo +2 位作者 ZHAO Quanbin CHEN Weixiong YAN Junjie 《Journal of Thermal Science》 SCIE EI CAS CSCD 2021年第2期394-417,共24页
Liquid Droplet Radiator (LDR) system is regarded as a quite promising waste heat rejection system for aerospace engineering.A comprehensive review on the state-of-the-art of LDR system was carried out.The thermal desi... Liquid Droplet Radiator (LDR) system is regarded as a quite promising waste heat rejection system for aerospace engineering.A comprehensive review on the state-of-the-art of LDR system was carried out.The thermal design considerations of crucial components such as working fluid,droplet generator and collector,intermediate heat exchanger,circulating pump and return pipe were reviewed.The state-of-the-art of existing mathematical models of radiation and evaporation characteristics of droplet layer from literatures were summarized.Furthermore,thermal designs of three LDR systems were completed.The weight and required planform area between the rectangular and triangular LDR systems were respectively compared and the evaporation models for calculating the mass loss were evaluated.Based on the review,some prospective studies of LDR system were put forward in this paper. 展开更多
关键词 liquid Droplet Radiator(LDR)system thermal design considerations radiative heat transfer evaporation loss
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RNA 5-methylcytosine regulates YBX2-dependent liquid-liquid phase separation
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作者 Xiuzhi Wang Mengke Wang +12 位作者 Xinyuan Dai Xiao Han Yu Zhou Weiyi Lai Liyuan Zhang Ying Yang Yusheng Chen Hailin Wang Yong Liang Zhao Bin Shen Yuhan Zhang Ying Huang Yun-Gui Yang 《Fundamental Research》 CAS 2022年第1期48-55,共8页
5-Methylcytosine(m^(5)C)is one of the most prevalent internal modifications of messenger RNA(mRNA)in higher eukaryotes.Here we report that Y box protein 2(YBX2)serves as a novel mammalian m^(5)C binding protein to und... 5-Methylcytosine(m^(5)C)is one of the most prevalent internal modifications of messenger RNA(mRNA)in higher eukaryotes.Here we report that Y box protein 2(YBX2)serves as a novel mammalian m^(5)C binding protein to undergo liquid-liquid phase separation(LLPS)both in vivo and in vitro,and this YBX2-dependent LLPS is enhanced by m^(5)C marked RNA.Furthermore,the crystal structure assay revealed that W100,as a distinct m^(5)C binding site of YBX2,is critical in mediating YBX2 phase separation.Our study resolved the relationship between RNA m^(5)C and phase separation,providing a clue for a new regulatory layer of epigenetics. 展开更多
关键词 RNA modification RNA m^(5)C YBX2 Phase separation liquid droplet
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Phase separation in plants:New insights into cellular compartmentalization 被引量:7
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作者 Xiumei Xu Canhui Zheng +2 位作者 Dandan Lu Chun‐Peng Song Lixin Zhang 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2021年第11期1835-1855,共21页
A fundamental challenge for cells is how to coordinate various biochemical reactions in space and time. To achieve spatiotemporal control, cells have developed organelles that are surrounded by lipid bilayer membranes... A fundamental challenge for cells is how to coordinate various biochemical reactions in space and time. To achieve spatiotemporal control, cells have developed organelles that are surrounded by lipid bilayer membranes. Further, membraneless compartmentalization, a process induced by dynamic physical association of biomolecules through phase transition offers another efficient mechanism for intracellular organization. While our understanding of phase separation was predominantly dependent on yeast and animal models, recent findings have provided compelling evidence for emerging roles of phase separation in plants. In this review, we first provide an overview of the current knowledge of phase separation, including its definition, biophysical principles, molecular features and regulatory mechanisms. Then we summarize plant-specific phase separation phenomena and describe their functions in plant biological processes in great detail. Moreover, we propose that phase separation is an evolutionarily conserved and efficient mechanism for cellular compartmentalization which allows for distinct metabolic processes and signaling pathways, and is especially beneficial for the sessile lifestyle of plants to quickly and efficiently respond to the changing environment. 展开更多
关键词 cellular compartmentalization changing environment CONDENSATES liquid droplets phase separation
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