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On the MHD squeeze flow between two parallel disks with suction or injection via HAM and HPM

null

《机械工程前沿（英文）》 2014年 第9卷 第3期   页码 270-280 doi: 10.1007/s11465-014-0303-0

摘要：

An analysis has been performed to study the problem of magneto-hydrodynamic (MHD) squeeze flow of an electrically conducting fluid between two infinite, parallel disks. The analytical methods called Homotopy Analysis Method (HAM) and Homotopy Perturbation Method (HPM) have been used to solve nonlinear differential equations. It has been attempted to show the capabilities and wide-range applications of the proposed methods in comparison with a type of numerical analysis as Boundary Value Problem (BVP) in solving this problem. Also, the velocity fields have been computed and shown graphically for various values of physical parameters. The objective of the present work is to investigate the effect of squeeze Reynolds number, Hartmann number and the suction/injection parameter on the velocity field. Furthermore, the results reveal that HAM and HPM are very effective and convenient.

关键词： Homotopy Analysis Method     Homotopy Perturbation Method     incompressible flow     magneto-hydrodynamic flow     parallel disks    

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Method of internal 3D flow field numerical simulation for hydrodynamic torque converter

SHANG Tao, ZHAO Dingxuan, ZHANG Yuankun, GUO Xiangen, SHI Xiangzhong

《机械工程前沿（英文）》 2008年 第3卷 第1期   页码 86-90 doi: 10.1007/s11465-008-0012-7

摘要： To enhance the performance of a hydrodynamic torque converter and thoroughly understand the trait of inside flow, a numerical simulation method of internal 3D flow for the three-element centrifugal hydrodynamic torque converter was systematically researched and expatiated in this paper. First, the internal flow field of each impeller was calculated. The curves that illustrate the relationships between the pressure differences of the inlet and outlet versus flux were drawn. Second, the concurrent working point of each impeller was approximately estimated. Finally, a calculation was performed considering the influence on each impeller. The flow field of a working point was solved by multiple calculations and the actual working condition was gradually determined. The pressure and velocity distributions of the flow field were proposed. The performance parameters of the hydrodynamic torque converter were predicted. The calculation method, and the proposed pressure and velocity distribution of the flow field, have practical significance for the design and improvement of a hydrodynamic torque converter.

关键词： velocity distribution     calculation     numerical simulation     three-element centrifugal     converter    

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Effects of alfalfa coverage on runoff, erosion and hydraulic characteristics of overland flow on loess

Shufang WU, Pute WU, Hao FENG, G. P. Merkley

《环境科学与工程前沿（英文）》 2011年 第5卷 第1期   页码 76-83 doi: 10.1007/s11783-011-0282-x

摘要： An evaluation of the interactions between vegetation, overland and soil erosion can provide valuable insight for the conservation of soil and water. An experiment was conducted to study water infiltration, runoff generation process, rate of sediment erosion, and hydrodynamic characteristics of overland flow from a sloping hillside with different draw-off discharges from alfalfa and control plots with 20° slope. The effect of alfalfa on runoff and sediment transport reduction was quantitatively analyzed. Alfalfa was discussed for its ability to reduce the overland flow scouring force or change the runoff movement. Compared to the bare-soil plots, alfalfa plots generated a 1.77 times increase in infiltration rate. Furthermore, the down-slope water infiltration rate for the bare soil plots was higher than in the up-slope, while the opposite was found in the alfalfa plots. In addition, alfalfa had a significant effect on runoff and sediment yield. In comparison to the control, the runoff coefficient and sediment transportation rate decreased by 28.3% and 78.4% in the grass slope, respectively. The runoff generated from the alfalfa and bare-soil plots had similar trends with an initial increase and subsequent leveling to a steady-state rate. The transport of sediment reduced with time as a consequence of the depletion of loose surface materials. The maximum sediment concentration was recorded within the first few minutes of each event. The alfalfa plots had subcritical flow while the bare-soil plots had supercritical flow, which indicate that the capability of the alfalfa slope for resisting soil erosion and sediment movement was greater than for bare soil plots. Moreover, the flow resistance coefficient and roughness coefficient for the alfalfa plots were both higher than for the bare-soil plots, which indicate that overland flow in alfalfa plots had retarded and was blocked, and the flow energy along the runoff path had gradually dissipated. Finally, the ability to erode and transport sediment had decreased.

关键词： alfalfa     soil erosion     runoff and sedimentation     soil water infiltration     overland flow     hydrodynamic characteristics    

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Vibration control of a structure using Magneto-Rheological grease damper

Shinya SUGIYAMA, Tomoki SAKURAI, Shin MORISHITA

《机械工程前沿（英文）》 2013年 第8卷 第3期   页码 261-267 doi: 10.1007/s11465-013-0268-4

摘要：

This paper describes an application study of Magneto-Rheological (MR) grease damper to a structure with three stories. MR fluid is known as one of successful smart materials whose rheological properties can be varied by magnetic field strength, and has been applied to various kinds of device such as dampers, clutches, engine mounts, etc. However, ferromagnetic particles dispersed in MR fluid settle out of the suspension after a certain interval due to the density difference between the particles and their career fluid. To overcome this defect, we have developed a new type of controllable working fluid using grease as the career of magnetic particles. Network of thickener in grease is expected to hold the magnetic particles and prevent them from settled down. No or little sedimentation was observed in MR grease whose characteristics could be controlled by the magnetic field strength. MR grease was introduced into a cylindrical damper and its performance was studied. As a result, it was confirmed that the damping force of MR grease damper could be controlled by the applied electric current to the coil in the cylinder of damper. Furthermore, vibration response of a three-story model structure equipped with MR grease damper was investigated experimentally, and it was shown that MR grease damper worked effectively as a semi-active damper.

关键词： vibration control     damper     smart material     Magneto-Rheological (MR) grease     MR fluid    

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一种通用的基于斯托克斯流的复杂流束轮廓工程方法 Article

杨振宇, 南浪, 岑浩璋

《工程（英文）》 2021年 第7卷 第5期   页码 655-662 doi: 10.1016/j.eng.2021.02.008

摘要：

为了在微流控管道中实现诸如混合强化、反应控制和材料合成等应用，经常需要编辑其中的流束轮廓。传统的流束轮廓编辑方法通过激发惯性二次流，使管道中流体重新分布，然而在惯性流可以忽略的微流控环境中，难以借助这类方法形成流束轮廓。传统方法使用的对称式管道内结构也限制了可以创造的流束轮廓的多样性。此外，这类方法生成的每个流束轮廓均对应一个严格定义的特定流动环境，因而在有变化的流动环境中，难以再现这些轮廓。为了解决上述问题，我们提出一种基于非惯性二次流的工程方法来编辑流束轮廓：在微管道内部署一系列级联的具有不同几何形状的阶梯来操控处于斯托克斯流范围内的流体；通过调整这些微阶梯的形状可以定制输出任意的流束轮廓；设计数值式流束轮廓预测程序，可快速预测以任意次序排列的预定义的微阶梯所输出的流束轮廓。该方法可用于生成包括非对称流束轮廓在内的各种稳定的流束轮廓，并且广泛适用于多种微流控流动环境，促进对复杂微流场的预测和设计。

关键词： 微流控     流束轮廓     斯托克斯流     流体动力学聚焦     流动塑形    

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Synthesis of novel magneto-hybrid polyoxometalate composite membrane with simultaneous photocatalytic

《化学科学与工程前沿（英文）》 2023年 第17卷 第10期   页码 1450-1459 doi: 10.1007/s11705-023-2310-3

摘要： Membrane technology is ideal for removing aqueous humic acid, but humic acid deposits cause membrane fouling, a significant challenge that limits its application. Herein, this work proposed an alternative approach to the controllably magnetically induced magneto-hybrid polyoxometalate (magneto-HPOM) nanocomposite migration toward the polyethersulfone (PES) membrane surface under a magnetic field to enhance the self-cleaning and antifouling functionalities of the membrane. Before incorporating magneto-HPOM nanocomposite into the PES casting solution, functionalized magnetite nanoparticles (F-MNP) were first coated with HPOM photocatalyst to fabricate a magneto-HPOM-PES membrane. It was shown that the apparent impacts of this novel magneto-HPOM-PES membrane on the hydrophilic behavior and photocatalytic properties of the magneto-HPOM nanocomposite improve the hydrophilicity, separation performance, antifouling and self-cleaning properties of the membrane compared with neat PES membrane. Furthermore, after exposure to ultraviolet light, the magneto-HPOM-PES membrane can be recovered after three cycles with a flux recovery ratio of 107.95%, 100.06%, and 95.56%, which is attributed to the temporal super hydrophilicity effect. Meanwhile, the magneto-HPOM-PES membrane could efficiently maintain 100% humic acid rejection for the first and second cycles and 99.81% for the third cycle. This study revealed a novel approach to fabricating membranes with high antifouling and self-cleaning properties for water treatment.

关键词： magneto-hybrid polyoxometalate nanocomposite     composite membrane     antifouling     self-cleaning     magnetic and photocatalytic responsiveness    

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Effect of magneto rheological damper on tool vibration during hard turning

P. Sam PAUL, A. S. VARADARAJAN

《机械工程前沿（英文）》 2012年 第7卷 第4期   页码 410-416 doi: 10.1007/s11465-012-0341-4

摘要：

Recently, the concept of hard turning has gained considerable attention in metal cutting as it can apparently replace the traditional process cycle of turning, heat treating, and finish grinding for assembly of hard wear resistant steel parts. The present investigation aims at developing a magneto rheological (MR) fluid damper for suppressing tool vibration and promoting better cutting performance during hard turning. The magneto rheological Fluid acts as a viscoelastic spring with non-linear vibration characteristics that are controlled by the composition of the magneto rheological fluid, the shape of the plunger and the electric parameters of the magnetizing field. Cutting experiments were conducted to arrive at a set of electrical, compositional and shape parameters that can suppress tool vibration and promote better cutting performance during turning of AISI 4340 steel of 46 HRC with minimal fluid application using hard metal insert with sculptured rake face. It was observed that the use of MR fluid damper reduces tool vibration and improves the cutting performance effectively. Also commercialization of this idea holds promise to the metal cutting industry.

关键词： tool vibration     magneto rheological damper     hard turning     surface finish     tool wear    

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Recent progress in hydrodynamic characteristics research and application of annular centrifugal extractors

《化学科学与工程前沿（英文）》 2022年 第16卷 第6期   页码 854-873 doi: 10.1007/s11705-022-2156-0

摘要： The annular centrifugal extractor (ACE) integrates mixing and separation. It has been widely used in many industrial fields because of its low residence time, compact structure, and high mass transfer efficiency. Most of the literature has focused on flow instabilities, flow visualization, and computational fluid dynamics simulations. More recently, research on hydrodynamic behavior and structural optimization has received widespread attention. With the development of ACE technology, applications have been broadened into several new areas. Hence, this paper reviews research progress regarding ACE in terms of hydrodynamic characteristics and the structural improvements. The latest applications covering hydrometallurgy, nuclear fuel reprocessing, bio-extraction, catalytic reaction, and wastewater treatment are presented. We also evaluate future work in droplet breakup and coalescence mechanisms, structural improvements specific to different process requirements, scaling-up methods, and stability and reliability after scaling-up.

关键词： annular centrifugal extractor     hydrodynamic characteristics     structure optimization     the latest application    

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Polymer nanocomposites for microactuation and magneto-electric transduction

Kaori YUSE, Benoit GUIFFARD, Rabah BELOUADAH, Lionel PETIT, Laurence SEVEYRAT, Daniel GUYOMAR

《机械工程前沿（英文）》 2009年 第4卷 第3期   页码 350-354 doi: 10.1007/s11465-009-0056-3

摘要： In the last decade, electroactive polymers have attracted much attention especially because of their very actuating capabilities. Large strain is experimentally observed, but under quite high electrical field, which can be a severe drawback for actuating applications. First part of the present paper is concerned with the reduction of applied field onto electroactive polymer films to get a given strain level. Polyurethane (PU) films filled with carbon black (CB) nanoparticles exhibit relatively high strain level under a field of only 12.5 kV/mm. The simple easy-to-make method solution cast method was applied. Even though the generated stress level is still quite low, the present work shows high strain level under quite low field appliance by easy manufacturing, lightweight, and flexible polymer film. Besides, another interest of the present paper is in magneto-elasto-electric effect of a polymer film filled with some magnetic nano particles. Films filled with nonpiezoelectric but with magnetite particles has still short history. With the use of magneto materials, a large magnetic DC bias field is generally required, and it causes big problem on application. The films filled with some magnetite nanoparticles (Fe3O4 and Nickel) are fabricated then examined. It is clearly demonstrated that our films do not require any DC bias. Although linear polarization value is relatively small, the first step of the studies on magnetite nano-filled film is presented.

关键词： electroactive polymers     carbon filling     actuator     nanocarbon     electromechanical coupling     dielectric polymer actuators     polymer actuators     microactuation     magneto-electric effect    

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Identification of pollution sources in rivers using a hydrodynamic diffusion wave model and improved

《环境科学与工程前沿（英文）》 2023年 第17卷 第7期 doi: 10.1007/s11783-023-1685-1

摘要：

● A hydrodynamic-Bayesian inference model was developed for water pollution tracking.

关键词： Identification of pollution sources     Water quality restoration     Bayesian inference     Hydrodynamic model     Inverse problem    

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Numerical analysis of hydrodynamic process of circular-translational-moving polishing (CTMP)

ZHAI Wenjie, LIU Changxiong, LIANG Yingchun

《机械工程前沿（英文）》 2008年 第3卷 第4期   页码 441-448 doi: 10.1007/s11465-008-0074-6

摘要： By keeping a pad moving relative to a wafer along a circular path without rotation, we developed a polishing technique called circular-translational-moving polishing (CTMP), which permits multidirectional polishing of the work piece and thus bears the advantage of isotropic polishing and a potential increase of material removal rate (MRR) on the wafer. To illuminate the mechanisms of CTMP and determine the optimum process variables in a CTMP process, a three-dimensional hydrodynamic lubrication model for CTMP with a smooth and rigid pad under a quasi-stable state is established in a polar coordinate system. The model equations are further calculated numerically by the finite difference method. The instantaneous distribution of fluid pressure is obtained, which shows that a negative pressure exists. The reason for negative pressure in CTMP and its effect on polishing is discussed. Moreover, the nominal clearance of the fluid film, roll, and pitch angles under different working conditions are obtained in terms of the applied load, moments, and polishing velocity. The obtained numerical analysis can be used as guidance for choosing operation parameters in a practical CTMP application.

关键词： numerical analysis     practical CTMP     circular-translational-moving polishing     CTMP     different    

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Uncertainty quantification of stability and damage detection parameters of coupled hydrodynamic-ground

Nazim Abdul NARIMAN, Tom LAHMER, Peyman KARAMPOUR

《结构与土木工程前沿（英文）》 2019年 第13卷 第2期   页码 303-323 doi: 10.1007/s11709-018-0462-x

摘要： In this paper, models of the global system of the Koyna dam have been created using ABAQUS software considering the dam-reservoir-foundation interaction. Non coupled models and the coupled models were compared regarding the horizontal displacement of the dam crest and the differential settlement of the dam base in clay foundation. Meta models were constructed and uncertainty quantification process was adopted by the support of Sobol’s sensitivity indices considering five uncertain parameters by exploiting Box-Behnken experimental method. The non coupled models results determined overestimated predicted stability and damage detection in the dam. The rational effects of the reservoir height were very sensitive in the variation of the horizontal displacement of the dam crest with a small interaction effect with the beta viscous damping coefficient of the clay foundation. The modulus of elasticity of the clay foundation was the decisive parameter regarding the variation of the differential settlement of the dam base. The XFEM approach has been used for damage detection in relation with both minimum and maximum values of each uncertain parameter. Finally the effects of clay and rock foundations were determined regarding the resistance against the propagation of cracks in the dam, where the rock foundation was the best.

关键词： massed foundation     hydrodynamic pressure     Box-Behnken method     meta model     Sobol’s sensitivity indices    

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Scenario analysis of water pollution control in the typical peri-urban river using a coupled hydrodynamic-water

Haifeng JIA, Shuo WANG, Mingjie WEI, Yansong ZHANG

《环境科学与工程前沿（英文）》 2011年 第5卷 第2期   页码 255-265 doi: 10.1007/s11783-010-0279-x

摘要： The water quality pollution and ecological deterioration in peri-urban rivers are usually serious under rapid urbanization and economic growth. In the study, a typical peri-urban river, Nansha River, was selected as a case study to discuss the scheme of peri-urban river rehabilitation. Located in the north part of the Beijing central region, the Nansha River watershed has been designated as an ecologically friendly garden-style area with high-tech industry parks and upscale residential zones. However, the Nansha River is currently seriously contaminated by urban and rural pollutants from both nonpoint sources (NPS) and point sources (PS). In this study, the pollutant loads from point sources and nonpoint sources in the Nansha River watershed were first assessed. A coupled model, derived from the Environmental Fluid Dynamics Code and Water Quality Analysis Simulation Program, was developed to simulate the hydrodynamics and water quality in the Nansha River. According to the characteristics of the typical peri-urban river, three different PS and NPS control scenarios were designed and examined by modeling analyses. Based on the results of the scenario analysis, a river rehabilitation scheme was recommended for implementation.

关键词： peri-urban river     coupled hydrodynamic-water quality modeling     scenario analysis     river rehabilitation    

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Development of a hydrodynamic model and the corresponding virtual software for dual-loop circulating

Shanwei Hu, Xinhua Liu

《化学科学与工程前沿（英文）》 2021年 第15卷 第3期   页码 579-590 doi: 10.1007/s11705-020-1953-6

摘要： Dual-loop circulating fluidized bed (CFB) reactors have been widely applied in industry because of their good heat and mass transfer characteristics and continuous handling ability. However, the design of such reactors is notoriously difficult owing to the poor understanding of the underlying mechanisms, meaning it has been heavily based on empiricism and stepwise experiments. Modeling the gas-solid CFB system requires a quantitative description of the multiscale heterogeneity in the sub-reactors and the strong coupling between them. This article proposed a general method for modeling multi-loop CFB systems by utilizing the energy minimization multiscale (EMMS) principle. A full-loop modeling scheme was implemented by using the EMMS model and/or its extension models to compute the hydrodynamic parameters of the sub-reactors, to achieve the mass conservation and pressure balance in each circulation loop. Based on the modularization strategy, corresponding interactive simulation software was further developed to facilitate the flexible creation and fast modeling of a customized multi-loop CFB reactor. This research can be expected to provide quantitative references for the design and scale-up of gas-solid CFB reactors and lay a solid foundation for the realization of virtual process engineering.

关键词： multi-loop circulating fluidized bed     mathematical modeling     energy minimization multiscale     virtual fluidization     mesoscale structure    

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Creep and recovery behaviors of magnetorheological elastomers

Weihua LI, Yang ZHOU, Tongfei TIAN, Gursel ALICI,

《机械工程前沿（英文）》 2010年 第5卷 第3期   页码 341-346 doi: 10.1007/s11465-010-0096-8

摘要： This paper presents experimental and modeling study of creep and recovery behaviors of magneto-rheological elastomers (MREs) under constant stresses. Experimental study was accomplished using a rheometer with parallel-plate geometry. Under constant stresses ranging from a small value to a large one, the resultant strains were recorded. The experimental results demonstrated that MREs behave as linear visocleastic properties. The effects of the magnetic field and stress on MRE creep behaviors were discussed. Moreover, a four-parameter viscoelastic model was developed to describe MRE creep behaviors. The comparison between the experimental results and the modeling predictions indicates that the model can predict MRE creep behaviors very well.

关键词： magneto-rheological elastomers (MREs)     creep     recovery     linear viscoelastic model    

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标题 作者 时间 类型 操作

On the MHD squeeze flow between two parallel disks with suction or injection via HAM and HPM

null

期刊论文

Method of internal 3D flow field numerical simulation for hydrodynamic torque converter

SHANG Tao, ZHAO Dingxuan, ZHANG Yuankun, GUO Xiangen, SHI Xiangzhong

期刊论文

Effects of alfalfa coverage on runoff, erosion and hydraulic characteristics of overland flow on loess

Shufang WU, Pute WU, Hao FENG, G. P. Merkley

期刊论文

Vibration control of a structure using Magneto-Rheological grease damper

Shinya SUGIYAMA, Tomoki SAKURAI, Shin MORISHITA

期刊论文

一种通用的基于斯托克斯流的复杂流束轮廓工程方法

杨振宇, 南浪, 岑浩璋

期刊论文

Synthesis of novel magneto-hybrid polyoxometalate composite membrane with simultaneous photocatalytic

期刊论文

Effect of magneto rheological damper on tool vibration during hard turning

P. Sam PAUL, A. S. VARADARAJAN

期刊论文

Recent progress in hydrodynamic characteristics research and application of annular centrifugal extractors

期刊论文

Polymer nanocomposites for microactuation and magneto-electric transduction

Kaori YUSE, Benoit GUIFFARD, Rabah BELOUADAH, Lionel PETIT, Laurence SEVEYRAT, Daniel GUYOMAR

期刊论文

Identification of pollution sources in rivers using a hydrodynamic diffusion wave model and improved

期刊论文

Numerical analysis of hydrodynamic process of circular-translational-moving polishing (CTMP)

ZHAI Wenjie, LIU Changxiong, LIANG Yingchun

期刊论文

Uncertainty quantification of stability and damage detection parameters of coupled hydrodynamic-ground

Nazim Abdul NARIMAN, Tom LAHMER, Peyman KARAMPOUR

期刊论文

Scenario analysis of water pollution control in the typical peri-urban river using a coupled hydrodynamic-water

Haifeng JIA, Shuo WANG, Mingjie WEI, Yansong ZHANG

期刊论文

Development of a hydrodynamic model and the corresponding virtual software for dual-loop circulating

Shanwei Hu, Xinhua Liu

期刊论文

Creep and recovery behaviors of magnetorheological elastomers

Weihua LI, Yang ZHOU, Tongfei TIAN, Gursel ALICI,

期刊论文