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The influence of joint geometric parameters on shape factor of butt joint with center through crack

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China Welding 2012年第2期21卷 52-54页

作者：张敬强杨建国王涛刘雪松董志波方洪渊 Dong Zhibo and Fang Hongyuan State Key Laboratory of AdvaneedWelding and JoiningHarbin Institute of TechnologyHarbin150001 Jiamusi University Jiamusi154007

In this research, the influence of such joint geometric parameters as weld width and reinforcement on shape ~actor of butt joint with center crack subjected to static loading was investigated by finite element analyses method. According to the analytical resuhs, a well fracture resistant joint shape of butt joint with center crack has been approved.

关键词： joint geometric parameters butt joint with center crack shape factor

Numerical investigation of the influence of kinetics and shape factor on barium sulfate precipitation in a continuous stirred tank

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Frontiers of Chemical Science and Engineering 2009年第3期3卷 272-281页

作者： Zheng WANG Zai-Sha MAO Chao YANG Qinghua ZHANG Jingcai CHENG National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China State Key Laboratory of Chemical Safety and Control SINOPEC Qingdao Research Institute of Safety EngineeringQingdao 266071China

The effect of kinetics and shape factor on barium sulfate precipitation in a continuous stirred tank has been investigated numerically through solving the standard momentum and mass transport equations in combination with the moment equations for crystal population balance.The numerical method was validated with the literature data.The simulated results include the distribution of the local supersaturation ratio in the reactor,the mean crystal size,and the coefficient of variation.The simulation results show that the value of shape factor used in the model affected greatly the mean crystal size and the moments of the crystal size distribution.The influence of the kinetic expressions on the simulation is also analyzed.It is important to investigate the relationship of the shape factor with the precipitator type and other operation conditions to obtain reliable simulation results and suitable kinetic equations of crystal nucleation and growth rates.

关键词： stirred tank numerical simulation precipita-tion shape factor crystal kinetics

Non-Darcy Flow in Molding Sands

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Open Journal of Applied Sciences 2024年第4期14卷 976-982页

作者： Miguel A. Barron-Meza Joan Reyes-Miranda Daniel Flores-Sanchez Departamento de Materiales Universidad Autonoma Metropolitana Azcapotzalco Ciudad de Mexico Mexico

Darcy’s law is widely used to describe the flow in porous media in which there is a linear relationship between fluid velocity and pressure gradient. However, it has been found that for high numbers of Reynolds this law ceases to be valid. In this work, the Ergun equation is employed to consider the non-linearity of air velocity with the pressure gradient in casting sands. The contribution of non-linearity to the total flow in terms of a variable defined as a non-Darcy flow fraction is numerically quantified. In addition, the influence of the shape factor of the sand grains on the non-linear flow fraction is analyzed. It is found that for values of the Reynolds number less or equal than 1, the contribution of non-linearity for spherical particles is around 1.15%.

关键词： Darcy’s Law Molding Sands Non-Darcy Flow Reynolds Number shape factor

Efficient fabrication of semisolid nondendritic Al alloy slurry with high quality

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China Foundry 2022年第2期19卷 117-130页

作者： Zong-xu Zhang Ti-jun Chen Kun Liu Han Xue Jia-chen Qi Guang-li Bi Ying Ma State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou 730050China

Subjecting a normal mechanical vibration to a cooling slope plate,is a proposed method for preparing semisolid nondendritic slurry,named shear-vibration coupling sub-rapid solidification(SCS).Taking Al-8Si alloy as model material,the temperature field and distribution field of solid or liquid phase during SCS were simulated using COMSOL Multiphysics software to primarily choose the optimal processing parameters.Subsequently,the slurries were prepared with the parameters selected according to the simulation results and the microstructures of the slurries were experimentally investigated.Results indicate that the simulation results could provide a basis for roughly choosing the processing parameters,although the calculated solid fractions are always higher than the experimental ones.The processing parameters affect the primary grain size,shape factor and solid fraction mainly through altering the contact duration of melt on the plate,and thus affecting the cooling effect on the melt,nucleation rate,and grain dissociation and proliferation.Experiments with optimized processing parameters show that the primary grains in the slurry have an average size of about 32μm and shape factor of 1.38,and are quite uniform,even at the highest pouring rate of 2.81 kg·s^(-1),the size and shape factor are about 46μm and 1.7,respectively,which implies that the proposed SCS is a promising technology for efficient fabrication of high-quality Al slurry available for engineering applications.

关键词： semisolid nondendritic slurry semisolid forming simulation primary grains shape factor

Deposition of non-spherical microparticles in the human upper respiratory tract

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Particuology 2018年第1期16卷 185-189页

作者： Lixing Jia Lianzhong Zhang Suyuan Yu School of Physics Nankai University Tianjin 300071 China Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China

We investigated the deposition pattern of microparticles with different particle diameters, shape factors, and initial flow conditions in a realistic human upper respiratory tract model. We identified a close relationship between the deposition fraction and the particle shape factor. The deposition fraction of the particles decreased sharply with increasing particle shape factor because of the decreasing drag force. We also found that the deposition varied at different positions in the upper respiratory tract. At low shape factors, the highest fraction of particles deposited at the mouth and pharynx. However, with increasing shape factor, the deposition fraction in the trachea and lungs increased. Moreover, for a given shape factor, larger particles deposited at the mouth and pharynx, which indicates that the deposition fraction of microparticles in the human upper respiratory tract is affected first and foremost by particle inertia as well as by the drag force.

关键词： Particle deposition Non-spherical microparticles Human upper airway shape factor

Statistical Analysis of Reinforcement Characterization in SiC Particle Reinforced Al Matrix Composites

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Journal of Materials Science & Technology 2009年第6期25卷 807-813页

作者： Peng Zhang Fuguo Li School of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072 China

The characterization of reinforcement in 15% SiC particles reinforced AI matrix composites processed by powder metallurgy route was studied by statistical method. During the analysis, a new approach for the estimation of the characterization of reinforcement was presented. The mathematic software MATLAB was used to calculate the area and perimeter of reinforcement, in which the image processing technique was applied. Based on the calculation, the fractal dimension, shape factor, reinforcement size distribution and reinforcement distribution were investigated. The results show that the reinforcement shape is similar to rectangle; the reinforcement size distribution is broad with the＇ range of 1-12 μm; the topography of reinforcement is smooth; and the reinforcement distribution is inhomogeneous. Furthermore, the cell model based on the statistical characterization was established and tested.

关键词： Particle reinforced AI matrix composites Fractal dimension shape factor Distribution Cell model

Numerical investigations to design a novel model based on the fifth order system of Emden–Fowler equations

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Theoretical & Applied Mechanics Letters 2020年第5期10卷 333-342页

作者： Zulqurnain Sabir Mehmet Giyas Sakar Manshuk Yeskindirova Onur Saldir Department of Mathematics and Statistics Hazara UniversityMansehraPakistan Department of Mathematics Faculty of SciencesYuzuncu Yil UniversityVanTurkey Department of Translation Theory and Practice L.N.Gumilyov Eurasian National UniversityKazakhstan

The aim of the present study is to design a new fifth order system of Emden–Fowler equations and related four types of the model.The standard second order form of the Emden–Fowler has been used to obtain the new model.The shape factor that appear more than one time discussed in detail for every case of the designed model.The singularity atη=0 at one point or multiple points is also discussed at each type of the model.For validation and correctness of the new designed model,one example of each type based on system of fifth order Emden–Fowler equations are provided and numerical solutions of the designed equations of each type have been obtained by using variational iteration scheme.The comparison of the exact results and present numerical outcomes for solving one problem of each type is presented to check the accuracy of the designed model.

关键词： Fifth order Emden-Fowler system Multiple singularity shape factor Numerical experimentations Variational iteration scheme

Optimization of the Chemical Composition of Cast Iron Used for Casting Ball Bearing Grinding Disks

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Tsinghua Science and Technology 2008年第2期13卷 164-169页

作者： Aurel Crisan Sorin Ion Munteanu Ioan Ciobanu Iulian Riposan Department of Materials Science and Engineering Transilvania University Department of Materials Science and Engineering Politehnica University

The chemical composition of cast iron used for casting ball bearing machining disks was varied to optimize the properties such as castability, hardenability, and durability in ball machining. The cast iron characteristics were most strongly dependent on the Ni content and the carbon saturation degree, So. This paper describes the types of test specimens, the working conditions, and the experimental results. The increase of the degree of carbon saturation reduces the tendency to form shrinkholes in the castings. The decrease in the Ni content negatively affects the final hardening treatment. A way to control solidification defects in cast iron, by reducing the Ni content, has been verified on cast disks.

关键词： cast iron micro-shrinkhole shrinkage shape factor solidification

ANALYTICAL SOLUTION OF FLOW OF SECOND-ORDER NON-NEWTONIAN FLUIDS THROUGH ANNULAR PIPES

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Applied Mathematics and Mechanics(English Edition) 1993年第3期14卷 209-215页

作者：朱文辉刘慈群 National University of Defence Technology Changsha Institute of Porous Flow and Fluid Mechanics Langfang Hebei

This paper presents an analytical solution to the unsteady flow of the second-order non-Newtonian fluids by the use of intergral transformation method. Based on the numerical results, the effect of non-Newtonian coefficient Hc and other parameters on the flow are analysed. It is shown that the annular flow has a shorter characteristic time than the general pipe flow while the correspondent velocity, average velocity have a ... nailer value for a given Hc. Else, when radii ratio keeps unchanged, the shear stress of inner wall of annular flow will change with the inner radius -compared with the general pipe flow and is always smaller than that of the outer wall.

关键词： integral transformation shape factor non-Newtonian coefficient,second-order fluids annular pipes