作者：
Ding, Y.H.;Zhang, P.;Zhuo, Q.;Ren, H.M.;Yang, Z.M.;Jiang, Y.
期刊：
NANOTECHNOLOGY,2011年22(21) ISSN：0957-4484
通讯作者：
Ding, Y. H.(yhding@yahoo.cn)
作者机构：
[ Ren, H.M. ; Ding, Y.H. ; Jiang, Y. ; Yang, Z.M. ; Zhuo, Q. ; Zhang, P. ] Institute of Rheology Mechanics, Xiangtan University, Hunan 411105, China;[Ding, Y.H. ] Chemical Process Simulation and Optimization Research Center, Ministry of Education, Xiangtan University, Hunan 411105, China;[ Yang, Z.M. ] College of Chemistry, Xiangtan University, Hunan 411105, China
期刊：
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics,2013年87(5) ISSN：1539-3755
通讯作者：
Luo, KH
作者机构：
[Luo, K. H.] Key Laboratory for Thermal Science and Power Engineering, Ministry of Education, Tsinghua University, Beijing 100084, China;[Luo, K. H.; Li, Q.] Energy Technology Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ, United Kingdom;[Li, X. J.] School of Civil Engineering and Mechanics, Xiangtan University, Xiangtan 411105, China
通讯机构：
[Luo, KH] Univ Southampton, Fac Engn & Environm, Energy Technol Res Grp, Southampton SO17 1BJ, Hants, England.
关键词：
Conceptual simplicity - Droplet oscillations - High Reynolds number - Interface thickness - Large density ratio - Lattice boltzmann models - Pseudopotential models - Thermodynamic consistency
摘要：
Owing to its conceptual simplicity and computational efficiency, the pseudopotential multiphase lattice Boltzmann (LB) model has attracted significant attention since its emergence. In this work, we aim to extend the pseudopotential LB model to simulate multiphase flows at large density ratio and relatively high Reynolds number. First, based on our recent work [Q. Li, K. H. Luo, and X. J. Li, Phys. Rev. E 86, 016709 (2012)], an improved forcing scheme is proposed for the multiple-relaxation-time pseudopotential LB model in order to achieve thermodynamic consistency and large density ratio in the model. Next, through investigating the effects of the parameter a in the Carnahan-Starling equation of state, we find that the interface thickness is approximately proportional to 1/root a. Using a smaller a will lead to a wider interface thickness, which can reduce the spurious currents and enhance the numerical stability of the pseudopotential model at large density ratio. Furthermore, it is found that a lower liquid viscosity can be gained in the pseudopotential model by increasing the kinematic viscosity ratio between the vapor and liquid phases. The improved pseudopotential LB model is numerically validated via the simulations of stationary droplet and droplet oscillation. Using the improved model as well as the above treatments, numerical simulations of droplet splashing on a thin liquid film are conducted at a density ratio in excess of 500 with Reynolds numbers ranging from 40 to 1000. The dynamics of droplet splashing is correctly reproduced and the predicted spread radius is found to obey the power law reported in the literature.
期刊：
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics,2012年86(1) ISSN：1539-3755
通讯作者：
Li, Q.
作者机构：
[ Luo, K.H. ] Center for Combustion Energy, Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China;[ Luo, K.H. ; Li, Q. ] Energy Technology Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ, United Kingdom;[ Li, X.J. ] School of Civil Engineering and Mechanics, Xiangtan University, Xiangtan 411105, China
通讯机构：
[Li, Q] Univ Southampton, Fac Engn & Environm, Energy Technol Res Grp, Southampton SO17 1BJ, Hants, England.
摘要：
The pseudopotential lattice Boltzmann (LB) model is a widely used multiphase model in the LB community. In this model, an interaction force, which is usually implemented via a forcing scheme, is employed to mimic the molecular interactions that cause phase segregation. The forcing scheme is therefore expected to play an important role in the pseudoepotential LB model. In this paper, we aim to address some key issues about forcing schemes in the pseudopotential LB model. First, theoretical and numerical analyses will be made for Shan-Chen's forcing scheme [Shan and Chen, Phys. Rev. E 47, 1815 (1993)] and the exact-difference-method forcing scheme [Kupershtokh et al., Comput. Math. Appl. 58, 965 (2009)]. The nature of these two schemes and their recovered macroscopic equations will be shown. Second, through a theoretical analysis, we will reveal the physics behind the phenomenon that different forcing schemes exhibit different performances in the pseudopotential LB model. Moreover, based on the analysis, we will present an improved forcing scheme and numerically demonstrate that the improved scheme can be treated as an alternative approach to achieving thermodynamic consistency in the pseudopotential LB model.
期刊：
Journal of Alloys and Compounds,2009年475(1-2):207-219 ISSN：0925-8388
通讯作者：
Long, Z.(longzl@xtu.edu.cn)
作者机构：
[ Wei, Hongqin ] Department of Mechanical and Energy Engineering, Shaoyang University, Shaoyang, Hunan 422000, China;[ Inoue, Akihisa ; Xie, Guoqiang ] Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan;[ Ding, Yanhuan ; Wei, Hongqin ; Long, Zhilin ; Zhang, Ping ] Institute of Fundamental Mechanics and Material Engineering, Xiangtan University, Xiangtan, Hunan 411105, China
通讯机构：
[Long, ZL] Xiangtan Univ, Inst Fdn Mech & Mat Engn, Xiangtan 411105, Hunan, Peoples R China.
期刊：
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY,2009年29(6):1029-1037 ISSN：0955-2219
通讯作者：
Sheng, Y
作者机构：
[Sheng, Yong] School of Civil Engineering, University of Leeds, Leeds, LS2 9JT, United Kingdom;[Yang, Dongmin; Tan, Yuanqiang] School of Mechanical Engineering, Xiangtan University, Hunan 411105, China
关键词：
SiC;Mechanical properties;Microstructure;Fracture;Discrete element method
摘要：
Discrete element method (DEM) was employed in the research works presented in this paper to simulate the microscopic machining process of ceramics. A densely packed particle assembly system of the polycrystalline SiC has been generated in DEM software package PFC2D using bonded-particle model (BPM) in order to represent for the ceramic part numerically. Microscopic mechanical properties of SiC were calibrated by comparing the numerical tests in PFC2D with the equivalent experimental results, and introduced into the subsequent modeling of the ceramic machining process. The dynamic process of initiation and propagation of the micro-cracks under various machining conditions has been explicitly modeled in the DEM simulations. The numerical results from DEM modeling agreed well with the experimental observations and theoretical predictions. Rational relations between cracking damage of ceramics and cutting conditions have been established based on the analysis of simulation results. A generalized model of defining the range of inelastic zone has also been developed based on the numerical results. Moreover, this study has demonstrated the advantage of DEM model in its capability of revealing the mechanical details of machining process at micro-scale. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.
期刊：
Energy and Environmental Science,2014年7(5):1700-1707 ISSN：1754-5692
通讯作者：
Zhao, CX
作者机构：
[Luo, Hean; Chen, Feng; Zhao, Caixian; You, Kuiyi] School of Chemical Engineering, Xiangtan University, Xiangtan 411105, China;[Chen, Feng; Zhao, Caixian; Zhang, Ping] School of Civil Engineering and Mechanics, Xiangtan University, Xiangtan 411105, China;[Yi, Lanhua] Department of Chemistry, Xiangtan University, Xiangtan 411105, China
关键词：
Carbon layers - Charge recombinations - Hydrogen production rate - Nano-structured - Solar water splitting - Ultra-violet light - Water splitting - Wide band gap
作者：
Wu, Lijuan;Xiao, Qizhen;Li, Zhaohui;Lei, Gangtie;Zhang, Ping;Wang, Li
期刊：
SOLID STATE IONICS,2012年215:24-28 ISSN：0167-2738
通讯作者：
Xiao, Q.(qizhenxiao2004@yahoo.com.cn)
作者机构：
[Wu, Lijuan ; Li, Zhaohui ; Xiao, Qizhen ; Wang, Li ; Lei, Gangtie ] College of Civil Engineering and Mechanics, Xiangtan University, Hunan 411105, China;[Wu, Lijuan ; Xiao, Qizhen ; Zhang, Ping ] Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105, China
作者机构：
[Yan, Wenjin; Liu, Gui; Huang, Jiangnan] College of Chemical Engineering, Xiangtan University, Hunan 411105, China;[Jiang, Yong; Long, Zhilin; Zhang, Ping; Ding, Yanhuai] College of Civil Engineering and Mechanics, Xiangtan University, Hunan 411105, China;[Jiang, Yong; Long, Zhilin; Zhang, Ping; Ding, Yanhuai] Institute of Fundamental Mechanics and Material Engineering, Xiangtan University, Hunan 411105, China
作者机构：
[Trias, Francesc Xavier; Oliva, Assensi; Zhang, Hao] Heat and Mass Transfer Technological Center, Technical University of Catalonia, Terrassa, 08222, Spain;[Yang, Dongmin; Tan, Yuanqiang; Jiang, Shengqiang; Zhang, Hao] School of Mechanical Engineering, Xiangtan University, Hunan 411105, China;[Sheng, Yong; Yang, Dongmin] School of Civil Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
关键词：
DEM;Puncture point location;Slurry velocity;Bend orientation
摘要：
A numerical simulation of fluid transportation process was carried out focused on the investigation into predicting the location of the puncture point location in elbow. The kinematics and trajectory of the discrete particles as well as the particle–particle interaction were described by discrete element method (DEM) while the hydrodynamic model of the fluid phase was based on the volume-averaged Navier–Stokes equations, and a fluid density-based buoyancy model was adopted to calculate the solid–fluid interaction force. In this paper, the spatial distribution of particle–wall interaction force was calculated and corresponded to the wear pattern in the elbow, the puncture point locations have been observed. In particular, the influences of slurry velocity, bend orientation and angle of elbow on the puncture point location were discussed.;Numerical simulations of fluid transportation process under different conditions were conducted. An investigation into predicting the location of the puncture point location in elbow has been carried out. Numerical results showed good agreements with that observed in actual industrial process.;;► A numerical simulation based on CFD and discrete element method was conducted. ► The solid-liquid interaction in fluid transportation progress was studied. ► The puncture point Location moves to downstream when slurry velocity increases. ► The puncture point location is significantly influenced by the bend orientation. ► Later half of the U-shaped suffers more frequently but lighter friction.
期刊：
Computers and Fluids,2014年94:37-48 ISSN：0045-7930
通讯作者：
Zhang, H
作者机构：
[Trias, Francesc Xavier; Zhang, Hao] Heat and Mass Transfer Technological Center, Technical University of Catalonia, Terrassa 08222, Spain;[Sheng, Yong; Yang, Dongmin] School of Civil Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom;[Tan, Yuanqiang] School of Mechanical Engineering in Xiangtan University, Hunan 411105, China;[Niu, Xiaodong; Li, Hao; Shu, Shi] School of Mathematics and Computational Science in Xiangtan University, Hunan 411105, China
通讯机构：
[Zhang, H] Tech Univ Catalonia, Heat & Mass Transfer Technol Ctr, Terrassa 08222, Spain.
关键词：
Particle collisions;Lattice Boltzmann method;Immersed boundary method;Discrete element method
摘要：
Particle collisions play a very important role in determining the fluid-particle multiphase flow, and thus it is crucial to treat the particle-particle interaction using a felicitous method in numerical simulations. A novel combined lattice Boltzmann method (LBM)-immersed boundary method (IBM)-discrete element method (DEM) scheme is presented in this study with its application to model the sedimentation of 2D circular particles in incompressible Newtonian flows. The hydrodynamic model of the incompressible Newtonian flow is based on the Bhatnagar-Gross-Krook LBM, and a momentum exchange-based IBM is adopted to calculate the fluid-solid interaction force. The kinematics and trajectory of the discrete particles are evaluated by DEM, in which the particle-particle interaction rules are governed by theoretical contact mechanics to enable the direct use of real particle properties. This eliminates the need of artificial parameters and also improves the reliability of the numerical results. By using a more accurate and physical description of particle interaction, a 'safe zone' or threshold is also no longer required. Case studies of single particle settling in a cavity, and two particles settling in a channel were carried out, the velocity characteristics of the particle during settling and near the bottom were examined. A numerical example of sedimentation involving 504 particles was finally presented to demonstrate the capability of the combined scheme. (C) 2014 Elsevier Ltd. All rights reserved.
期刊：
International Journal of Machine Tools and Manufacture,2008年48(9):975-982 ISSN：0890-6955
通讯作者：
Tan, Y.(tanyq@xtu.edu.cn)
作者机构：
[ Yang, Dongmin ; Tan, Yuanqiang ] School of Mechanical Engineering, Xiangtan University, Hunan 411105, China;[ Sheng, Y. ] School of Civil Engineering, University of Leeds, Leeds, LS2 9JT, United Kingdom
作者机构：
[Li, Zhaohui; Wang, Li; Xiao, Qizhen; Lei, Gangtie; Wu, Lijuan] Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105, China;[Xiao, Qizhen; Zhang, Ping] College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, China;[Xiao, Qizhen; Zhang, Ping] College of Civil Engineering and Mechanics, Xiangtan University, Hunan 411105, China
作者：
Zhongmei Yang;Ping Zhang;Yanhuai Ding;Yong Jiang;Zhilin Long;Wenli Dai
期刊：
Materials Research Bulletin,2011年46(10):1625-1631 ISSN：0025-5408
通讯作者：
Yang, Z.(kalimodor@163.com)
作者机构：
[Zhilin Long; Ping Zhang; Yong Jiang; Yanhuai Ding] Institute of Fundamental Mechanics and Materials Engineering, Xiangtan University, Xiangtan 411105, China;[Wenli Dai; Zhongmei Yang] College of Chemistry, Xiangtan University, Xiangtan 411105, China
关键词：
A. Nanostructures;A. Semiconductors;B. Chemical synthesis;C. X-ray diffraction
摘要：
We report a new method to synthesize Ag/ZnO heterostructures assisted by UV irradiation. The formation of Ag/ZnO heterostructures depends on photogenerated electrons produced by ZnO under UV light to reduce high valence silver. Functional property of the Ag/ZnO heterostructures is evaluated by photodegradation of methylene blue (MB) under UV illumination. Results of photodegradation tests reveal that the optimal photocatalytic activity of as-syntheszied samples is about 1.5 times higher than the pure ZnO synthesized in the same condition or commercial TiO2 (P-25), showing the advantage of the unique structure in the Ag/ZnO heterostructure. Besides, due to the reduced activation of surface oxygen atom, photocatalytic activity of the photocatalysts has no evident decrease even after three recycles.;;;► Fabrication of Ag/ZnO heterostructure between the two incompatible phases is realized under UV irradiation in the absence of surfactant. ► The synthetic method is facile, low cost, and low carbon, which depends on the photogenerated electrons produced by ZnO under UV light. ► Photocatalytic property of the as-synthesized samples is 3.0 times as good as the pure ZnO synthesized under the same condition or the commercial TiO2 (Degussa, P-25). ► The heterostructures exhibit good durability without significant change in the activity even after the third cycle compared to the pure ZnO.
摘要：
The isothermal section of the phase diagram of the ternary system Nd-Al-Si at 500 degreesC (Nd less than or equal to 50%, mole fraction) has been constructed on the basis of the data obtained by X-ray diffraction analysis, differential thermal analysis, metallographic examination, chemical analysis and electron micro-probe analysis. The obtained diagram consists of II single-phase regions, 21 two-phase regions and 11 three-phase regions. There exist two limit solid solutions. The intermetallic compound NdAl1.5Si0.5 has not been found in this section. No evidence of new phase has been observed in this work.
作者机构：
[Song, Junhua; Zhang, Hao; Tan, Yuanqiang; Jiang, Shengqiang] School of Mechanical Engineering, Xiangtan University, Hunan 411105, China;[Sheng, Yong; Yang, Dongmin] School of Civil Engineering, University of Leeds, Leeds L52 9jL, United Kingdom
摘要：
A numerical simulation has been conducted to study the solid-fluid multi-phase flow problem in concrete pumping process. The kinematics and trajectory of the discrete particles as well as the particle-particle interaction were predicted by DEM while the motion of the continuous fluid phase was evaluated by a Navier-Stokes solver, and a pressure gradient force model was adopted to calculate the solid-fluid interaction force. A case of pneumatic conveying was utilized to demonstrate the capability of the coupling model. The concrete pumping process was then simulated, where several flow features were observed such as roping, particle segregation and particle concentration. The frequency of the particles impacting on the bended pipe was monitored, a new time average collision intensity model based on impact force has been proposed to investigate the wear mechanism of the elbow. The location of maximum erosive wear damage in the elbow was predicted. Statistical results were in good agreement with that observed in actual pumping process. It is found that the present multi-phase coupling model can predict the wear behavior of the bended pipe accurately, and consequently provide an effective guidance for the design of concrete pumping pipe. (C) 2011 Elsevier Ltd. All rights reserved.