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FLOW PATTERNS AND FORCE CHARACTERISTICS OF LAMINAR FLOW PAST FOUR CYLINDERS IN DIAMOND ARRANGEMENT

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Journal of Hydrodynamics 2011年第1期23卷 55-64页

作者： ZOU Lin LIN Yu-feng LU Hong school of mechanical and Electronic engineering Wuhan University of Technology Wuhan 430070 China Department of mechanical engineering The Hong Kong Polytechnic University Hong Kong China

A three-dimensional numerical investigation of cross-flow past four circular cylinders in a diamond arrangement at Reynolds number of 200 is carried *** the spacing ratios（L /D）ranging from 1.2 to 5.0,the flow patterns can be classified into three basic *** critical spacing ratio for the transition from narrow gap flow pattern to vortex impingement flow pattern around the cylinders is found to beL /D=3.0,while a single bluff-body flow pattern is observed atL /D=*** relationship between the three-dimensional flow patterns and force characteristics around the four cylinders shows that the variation of forces and Strouhal numbers againstL /D are generally governed by these three kinds of flow *** is concluded that the spacing ratio has important effects on the development of the free shear layers about the cylinders and hence has significant effects on the force and pressure characteristics of the four cylinders with different spacing ratios.

关键词： four cylinders spacing ratio flow pattern force characteristics

Sintering technology for micro heat pipe with sintered wick

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Journal of Central South university 2010年第1期17卷 102-109页

作者：李西兵汤勇李勇周述璋曾志新 Department of mechanical and Power engineering Harbin University of Science and Technology school of mechanical engineering Qiqihar University school of mechanical and Automotive engineering South China University of Technology

In order to study reasonable sintering technological parameters and appropriate copper powder size range of micro heat pipe (MHP) with the sintered wick, the forming principle of copper powders in wicks and MHP's heat transfer capabilities were first analyzed, then copper powders with different cell sizes and dispersions were sintered in RXL-12-11 resistance furnace under the protection of the hydrogen at different sintering temperatures for different durations of sintering time, and finally the sintered wicks' scanning electron microscope (SEM) images and their heat transfer capabilities were analyzed. The results indicate that the wick sintered with copper powders of larger cell size or smaller size range has better sintering properties and larger heat transfer capabilities; and that the increase of either sintering temperatures or sintering time also helps to improve the wick's sintering properties and heat transfer capabilities, and the former affects more obviously than the latter. Considering both its manufacturing cost and performance requirements, it is recommended that copper powders with the size range of 140-170 μm are sintered at 900-950℃ for 30-60 min in practical manufacturing. In addition, two approaches to improve wick's porosity are also proposed through theoretical analysis, which suggests that the larger the wick's porosity, the better the heat transfer capabilities of the MHP.

关键词： micro heat pipe copper powders wick forming principle

Bionic Design and Finite Element Analysis of Elbow in Ice Transportation Cooling System

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Journal of Bionic engineering 2010年第3期7卷 301-306页

作者： Dejun Miao~(1,2), Xiuhua Sui~3, Linjing Xiao~3 1. Key Laboratory of Mine Hazard Prevention and Control (Ministry of Education, china), Shandong university of science and technology, Qingdao 266510, P. R. china 2. school of Architecture, Tsinghua university, Beijing 100084, P. R. china 3. College of mechanical and Electronic engineering, Shandong university of science and technology, Qingdao 266510, P. R. china Key Laboratory of Mine Hazard Prevention and Control (Ministry of Education China) Shandong University of Science and Technology Qingdao P. R. China school of Architecture Tsinghua University Beijing P. R. China College of mechanical and Electronic engineering Shandong University of Science and Technology Qingdao P. R. China

With the increase in mining depth, mine heat harm has appeared to be more prominent. The mine heat harm could be resolvedor reduced by ice refrigeration. Thus, ice transportation through pipeline becomes a critical problem; typically flowresistance occurs in the elbow. In the present study, according to the analysis of the surface morphology of fish scale, abiomimetic functional surface structure for the interior wall of elbow is designed. Based on the theory of liquid-solid two phaseflow, a CFD numerical simulation of ice-water mixture flowing through the elbow is carried out using finite element *** experiments of pressure drop and flow resistance for both bionic and common elbows are conducted to test theeffect of the bionic elbow on flow resistance reduction. It is found that with the increase in the ice mass fraction in the ice-watermixture, the effect of bionic elbow on resistance reduction becomes more obvious.

关键词： bionic elbow two phase flow ice transportation flow resistance reduction pressure loss

MODELING AND IMPLEMENTATION OF A DISTRIBUTED SHOP FLOOR MANAGEMENT AND CONTROL SYSTEM

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Chinese Journal of mechanical engineering 2002年第3期15卷 213-217页

作者： Liu Shiping Rao Yunqing Zhang Jie Li Peigenschool of mechanical science and engineering, Huazhong university of science and technology,Wuhan 430074, china school of mechanical science and engineering Huazhong University of Science and Technology Wuhan 430074

Adopting distributed control architecture is the important developmentdirection for shop floor management and control system, is also the requirement of making it agile,intelligent and concurrent. Some key problems in achieving distributed control architecture areresearched. An activity model of shop floor is presented as the requirement definition of theprototype system. The multi-agent based software architecture is constructed. How the core part inshop floor management and control system, production plan and scheduling is achieved. Thecooperation of different agents is illustrated. Finally, the implementation of the prototype systemis narrated.

关键词： Agent Shop floor management and control CIMS

Particle swarm optimization algorithm for partner selection in virtual enterprise

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Progress in Natural science:Materials International 2008年第11期18卷 1445-1452页

作者： Qiang Zhao~a Xinhui Zhang~(b,*) Renbin Xiao~c a school of mechanical science and engineering,Huazhong university of science and technology,Wuhan 430074,china b Department of Biomedical,Industrial & Human Factors engineering,Wright State university,Dayton,OH 45435,USA c Institute of Systems engineering,Huazhong university of science and technology,Wuhan 430074,china school of mechanical science and engineering Huazhong University of Science and Technology Wuhan 430074 China Department of Biomedical Industrial & Human Factors Engineering Wright State University Dayton OH 45435 USA Institute of Systems engineering Huazhong University of Science and Technology Wuhan 430074 China

Partner selection is a fundamental problem in the formation and success of a virtual *** partner selection problem with precedence and due date constraint is the basis of the various extensions and is studied in this paper.A nonlinear integer program model for the partner selection problem is *** problem is shown to be NP-complete by reduction to the knapsack problem,and therefore no polynomial time algorithm *** solve it efficiently,a particle swarm optimization(PSO)algorithm is adopted,and several mechanisms that include initialization expansion mechanism,variance mechanism and local searching mechanism have been developed to improve the performance of the proposed PSO algorithm.A set of experiments have been conducted using real examples and numerical simulation,and have shown that the PSO algorithm is an effective and efficient way to solve the partner selection problems with precedence and due date constraints.

关键词： Virtual enterprise Partner selection PSO NP-complete

Transient temperature field of a friction pair in a HVD device of a belt conveyor

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Mining science and technology 2010年第6期20卷 904-907页

作者： XIE Fangwei, HOU Youfu school of mechanical and Electrical engineering, china university of Mining & technology, Xuzhou 221008, china school of mechanical and Electrical engineering China University of Mining & Technology Xuzhou 221008 China

To show the distribution of a temperature field on a steel disk and to prolong the service life of a friction pair in a Hy-dro-Viscous Drive (HVD) device, a theoretical model of a transient temperature field was established, based on the theory of heat conduction. This theoretical model was solved using a finite element method. The results show that the surface temperature of the steel disk does not increase consistently as a function of the radius; the highest temperature appears short of the maximum radius. The relationship between the surface temperature and the mixed friction time is exponential. With a friction time of 15 s, the tem-perature reached 465.9 °C. Simultaneously, the internal thermal stress is larger than the yield stress of the material, causing a warping deformation of the steel disk. The largest axial deformation is 0.32 mm. The results of the experiment suggest that the de-formation is the same as that obtained from numerical simulation. Therefore, deformation of the steel disk must be considered dur-ing the study of the characteristics of a HVD.

关键词： hydro-viscous steel disk temperature field deformation numerical simulation

The precipitation and effect of nano nitrides in HSLC steel

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science china(Technological sciences) 2008年第7期51卷 989-998页

作者： FU Jie1, LIU YangChun1,2 & WU HuaJie1,3 1 school of Metallurgical and Ecological engineering, university of science and technology Beijing, Beijing 100083, china 2 Shougang technology Research Institute, Shougang (Group) Corporation, Beijing 100041, china 3 Metallurgical engineering Research Institute, university of science and technology Beijing, Beijing 100083, china school of Metallurgical and Ecological engineering University of Science and Technology Beijing Beijing China Shougang technology Research Institute Shougang (Group) Corporation Beijing China Metallurgical engineering Research Institute University of Science and Technology Beijing Beijing China

The existing forms of N and Al in HSLC (high strength low carbon) steel produced by TSCR (thin slab casting and rolling process), the precipitation thermodynamics and kinetics of AlN, and its effects on structure and mechanical property are studied. The experimental results show that only a small quantity of nitrogen is com- bined into AlN in HSLC steel produced by TSCR and most of the nitrogen in steel is still free nitrogen. Aluminum-nitride is mainly precipitated during the period of slow air cooling after coiling, but not during rolling and water cooling. The acid-soluble aluminum has no obvious effect on the grain size and mechanical property of HSLC steel produced by TSCR whose acid-soluble aluminum content is 0.005%―0.043%. The precipitation of AlN is not the main cause of grain refinement of HSLC steel produced by TSCR, nor is AlN the dominating precipitate that has precipitation strengthening effect. The nano nitrides are not pure AlN, but have complex compositions.

关键词： thin slab casting and rolling high strength low carbon steel AlN nano nitride precipitation strengthening

Research on the Long Time Swelling Properties of Poly (vinyl alcohol)/Hydroxylapatite Composite Hydrogel

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Journal of Bionic engineering 2009年第1期6卷 22-28页

作者： De-kun Zhang~(1,3), Da-gang Wang~2, Jun-jie Duan~(1,3), Shi-rong Ge~(2,3)1. school of Materials science and engineering, china university of Mining and technology, Xuzhou 221116, P. R. china2. school of mechanical and Electrical engineering, china university of Mining and technology, Xuzhou 221116, P. R. china3. Biotribology Center, National Key Laboratory of Tribology, Tsinghua university, Beijing 100083, P. R. china school of Materials science and engineering China University of Mining and Technology Xuzhou P. R. China Biotribology Center National Key Laboratory of Tribology Tsinghua University Beijing P. R. China school of mechanical and Electrical engineering China University of Mining and Technology Xuzhou P. R. China

Poly(vinyl alcohol)/hydroxylapatite(PVA/HA)composite hydrogel was prepared by repeated freezing and *** water loss properties of the resultant hydrogel were investigated by using optical *** time immersion tests of PVA/HA composite hydrogel were carried out in the diluted calf serum solution to study the change laws of swelling properties with the freezing-thawing cycles and HA *** micro-morphologies of PVA/HA composite hydrogel after long time immersion were observed by means of the high-accuracy 3D *** results show that the swelling process of PVA/HA composite hydrogel is the converse process of its water *** time swelling ratio curves of PVA/HA composite hydrogel in the calf serum solution are manifested as four stages of quick increase,decrease,slow decrease and stable balance,and its equilibrium swelling ratio decreases with the increase of freezing-thawing cycles and HA *** is revealed that the network structure of the composite hydrogel immersed for a long period is significantly improved with the increase of HA content. Perfect network structures of PVA/HA composite hydrogel as well as full and equilibrium tissues after swelling equilibrium are obtained when the HA content is 3% and the number of freezing-thawing cycles is 7.

关键词： poly (vinyl alcohol) hydroxyapatite composite hydrogel swelling property morphology

Effect of Preparation Methods on mechanical Properties of PVA/HA Composite Hydrogel

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Journal of Bionic engineering 2010年第3期7卷 235-243页

作者： Dekun Zhang~1, Junjie Duan~1, Dagang Wang~2, Shirong Ge~2 1. school of Materials science and engineering, china university of Mining and technology Xuzhou 221116, P. R. china 2. school of mechanical and Electrical engineering, china university of Mining and technology, Xuzhou 221116, P. R. china school of Materials science and engineering China University of Mining and Technology Xuzhou P. R. China school of mechanical and Electrical engineering China University of Mining and Technology Xuzhou P. R. China

Poly(vinyl alcohol) (PVA)/hydroxyapatite (HA) composite hydrogel specimens were prepared with 15% PVA and 1%,2%, 3%, 4% and 5% HA by repeated freezing-thawing. The tests of static and dynamic mechanical properties were carried out todiscuss the influence of different contents of HA and freezing-thawing cycles on the mechanical properties of PVA/HA compositehydrogel. The results of static mechanical tests showed that the PVA/HA composite hydrogel with 3% HA and ninefreezing-thawing cycles had excellent stress relaxation properties, higher relaxation ratio, lower stress equilibrium value andpresented better properties of creep and recovery. The results of dynamic mechanical test showed that the PVA/HA compositehydrogel with nine freezing-thawing cycles had higher storage modulus and loss modulus, so was the PVA/HA compositehydrogel with 3% HA.

关键词： composite hydrogel HA contents freezing-thawing cycles static properties dynamic properties