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International Journal of Minerals,Metallurgy and Materials 2011年第4期18卷 494-501页

作者： Xin-hui Si Lian-cunZheng Xin-xin Zhang Ying Chao Applied Science School University of Science and Technology Beijing Beijing 100083 China Department of Mechanical Engineering University of Science and Technology Beijing Beijing 100083 China Chemical Defense Institute of the PLA Beijing 102205 China

The asymptotic behavior of solutions of a similarity equation for the laminar flow in a porous channel with suction at both expanding and contracting walls has been obtained by using a singular perturbation ***,in the matching process,this solution neglects exponentially small *** take into account these exponentially small terms,a method involving the inclusion of exponentially small terms in a perturbation series was used to find two of the solutions *** series involving the exponentially small terms and expansion ratio predicts dual ***,the result indicates that the expansion ratio has much important influence on the solutions.

关键词： laminar flow porous channels multiple solutions singular perturbation method

Surface wettability and flow properties of non-metallic pipes in laminar flow

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Chinese Journal of Chemical Engineering 2020年第3期28卷 636-642页

作者： Hongyuan Qi Aiguo Liang Huayi Jiang Jianying Shi Nana Sun Yulong Wang College of Petroleum Engineering Xi'an Shiyou UniversityXi'an 710065China Shaanxi Key Laboratory of Advanced Stimulation Technology for Oil&Gas Reservoirs Xi'an Shiyou UniversityXi'an 710065China Karamay Hongshan Oilfield Co.Ltd. Karamay 834000China No.1 Production Plant Xinjiang Oilfield Branch CompanyKaramay 834000China

In this paper,three liquids flowing in five pipes with the same inner diameter of 14 mm were studied to determine the relationship between the surface wettability and flow properties in laminar flow(Re b 2000).This was motivated by oilfield observations of increased pressure drops in non-metallic pipes compared to those in metal pipes,which was contrary to expectations.A new expression for the frictional coefficient that considers the Reynolds number and contact angleθin laminar flow for non-metallic pipes was proposed based on the experimental results of single-phase flow using dimension and regression *** solutions of the anomalous phenomenon were proposed from the perspectives of the pipe diameter,contact-angle difference,and the compatibility between flexible composite pipe and JLHW105 oil according to the new *** surprising finding was that the surface wettability could control the frictional resistance by the critical contact angle(39.9°)obtained at the same Reynolds *** 0°bθ≤39.9°,the frictional coefficient increased as the contact angle *** contrast,if 39.9°bθb 180°,the frictional coefficient decreased with increasing contact *** influences of the pipe diameter and contactangle difference on the pressure drop difference of JLHW105 oil showed an inversely proportional relation.A series of materials and liquids were *** selection of pipe material for transporting a given fluid can be based on the contact angle,surface tension,and critical limit of the contact angle *** research results are expected to provide some guidelines for the selection of the appropriate pipe material for a given set of fluids.

关键词： Wettability Contact angle Frictional coefficient Fluid mechanics laminar flow Petroleum

Analytical solution for laminar flow through leaky tube

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Applied Mathematics and Mechanics(English Edition) 2011年第1期32卷 69-74页

作者： M.GORJI M.ALIPANAH M.SHATERI E.FARNAD Department of Mechanical Engineering Babol University of Technology Water and Westwater Company

The laminar flow through a leaky tube is investigated, and the momentum and conservation of energy equations are solved analytically. By using the Hagen-Poiseuille velocity profile and defining unknown functions for the axial and radial velocity compo- nents, the pressure and mass transfer equations are obtained, and their profiles are plotted according to different parameters. The results indicate that the axial velocity, the radial velocity, the mass transfer parameter, and the pressure in the tube decrease as the fluid moves along the tube.

关键词： leaky tube permeability mass transfer laminar flow analytical solution

ANALYTIC SOLUTIONS OF INCOMPRESSIBLE laminar flow IN THE INLET REGION OF A PIPE

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Applied Mathematics and Mechanics(English Edition) 2004年第8期25卷 894-897页

作者：孟庆国 Department of Mathematical and Physical Sciences National Natural Science Foundation of China Beijing 100085 P.R.China

The laminar analytic solutions of velocities and pressure in the central zone of the inlet region of pipe flow are given under the condition of uniform inflow, based on the Navier-Stokes equations of incompressible vi... 详细信息

关键词： pipe flow laminar flow inlet region analytic solution

Monitoring stratification of anode biofilms in bioelectrochemical laminar flow reactors using flow cytometry

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Environmental Science and Ecotechnology 2020年第4期4卷 18-25页

作者： Yuting Guo Luis FMRosa Susann Muller Falk Harnisch Department of Environmental Microbiology Helmholtz-Centre for Environmental Research e UFZPermoserstrasse 1504318LeipzigGermany

A laminar flow bioelectrochemical systems(BES)was designed and benchmarked using microbial anodes dominated with Geobacter *** reactor architecture was based on modeled flow fields,the resulting structure was 3D printed and used for BES *** of the substrate availability within the reactor channels led to heterogeneous biomass distribution,with the maximum biomass found mainly in the initial/middle *** anode performance was assessed for different hydraulic retention times while coulombic efficiencies of up to 100%(including also hydrogen recycling from the cathode)and current densities of up to 75 μA cm^(-2) at an anode surface to volume ratio of 1770 cm^(2) L^(-1) after 35 days were *** low current density can be clearly attributed to the heterogeneous distributions of biomass and the stratification of the microbial community ***,it was shown that time and space resolved analysis of the reactor microbiomes per channel is feasible using flow cytometry.

关键词： Microbial electrochemical technology flow cytometry laminar flow Microbial community Electroactive microorganisms

Pipes with Trapezoidal Cut Twisted Tape Inserts in the laminar flow Regime:Nusselt Number and Friction Coefficient Analysis

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Fluid Dynamics & Materials Processing 2023年第2期19卷 501-511页

作者： Shrikant Arunrao Thote Netra Pal Singh Department of Mechanical Engineering Oriental UniversityIndore453555India

The thermal behavior of pipes with a twisted tape inside(used to enhance heat transfer through the tube wall)is studied in the laminar flow *** is used as the work fluid with the corresponding Reynolds Number spanning the interval 200–*** is found that in such conditions the‘Nusselt Number’(Nu)gradually increases with reducing the tape twist ratio,whereas the friction factor is detrimentally affected by the presence of the tape(as witnessed by the comparison with the companion case where a plain tube is considered).In particular,it is shown that the heat transfer efficiency can be improved by nearly 69%if tape inserts with a relatively low twist ratio are *** the basis of these findings,it is concluded that loose fit tape inserts are superior to tight fit tapes in terms of heat transfer and ease of replacement.

关键词： Friction factor laminar flow Nusselt Number trapezoidal-cut twisted tape

Computational and experimental investigation of laminar flow mixing system in a pitched-blade turbine stirred tank

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International Journal of Agricultural and Biological Engineering 2018年第4期11卷 111-117页

作者： Yanyan Cui Huabo Zhang Xiwen Li Mingjin Yang Zailin Guan State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China College of Engineering and Technology Southwest UniversityChongqing 400715China

The flow distribution and mixing performance of the laminar flow in the PBT impeller-stirred tank were investigated in this *** variation along with mixing time of the flow distribution and concentration at the selected positions was visualized by means of the CFD and experiment *** CFD simulations results had a good agreement with the experimental *** order to minish the Segregated Regions,the PBT impeller was optimally designed by means of orthogonal factorial experiment with selecting theθ99 mixing time as evaluation *** the aim to increase the mixing efficiency,the optimal design results were obtained with the geometrical parameters of impeller diameter of 0.084 m,discharge angle of 45º,blade width of 0.018 m,and clearance of 0.05 m,and the mixing time of the optimal impeller-stirred flow was about 180 s,so this optimal design PBT impeller is more proper for the agricultural industries.

关键词： mixing laminar flow PBT impeller mixture homogeneity CFD

Analytical investigation of laminar flow through expanding or contracting gaps with porous walls

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Propulsion and Power Research 2014年第4期3卷 222-229页

作者： M.Jafaryar F.Farkhadnia E.Mohammadian M.Hosseini A.M.Khazaee Department of Mechanical Engineering Mazandaran Insitute of TechnologyBabol Iran Department of Mechanical Engineering Mechanics GroupRamsar BranchIslamic Azad UniversityRcmsarIran Deparment of Mechanical Engineering Islamic Azad UniversityQaemshahr BranchQaemshahrMazandaranIran Department of Mechanical Engineering Babol University of TechnologyBabolIran

laminar,isothermal,incompressible and viscous flow in a rectangular domain bounded by two moving porous walls,w hich enable the fuid to enter or exit during successive expansions or contractions is investigated analytically using optimal homotopy asymptotic method(OHAM).OHAM is a powerful method for solving nonlinear problems without depending to the small *** concept of this method is briefly introduced,and it's application for this problem is ***,the results are compared with numerical results and the validity of these methods is *** this verification,we analyze the effects of some physical applicable parameters to show the efficiency of OHAM for this type of *** results are presented to investigate the influence of the non-dimensional wall dilation rate(a)and pemeation Reynolds number(Re)on the velocity,normal pressure distribution and wall shear *** present problem for slowly expanding or contracting walls with weak permeability is a simple model for the transport of biological fuids through contracting or expanding vessels.

关键词： Optimal homotopy asymptotic method(OHAM) Viscous flow Permeation Reynolds number Non-dimensional wall dilation rate laminar flow Permeable channel

EXTRACTION　KINETICS　OF　RARE　EARTH（Ⅰ）　A　Constant　Interfacial　Cell　with　laminar　flow

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Acta Metallurgica Sinica(English Letters) 1995年第1期

ＥＸＴＲＡＣＴＩＯＮＫＩＮＥＴＩＣＳＯＦＲＡＲＥＥＡＲＴＨ（Ⅰ）ＡＣｏｎｓｔａｎｔＩｎｔｅｒｆａｃｉａｌＣｅｌｌｗｉｔｈＬａｍｉｎａｒＦｌｏｗ￥ＺＨＥＮＧＺｈｏｎｇ；ＬＩＤｅｑｉａｎ（ＣｈａｎｇｃｈｕｎＩｎｓｔｉｔｕ... 详细信息

ＥＸＴＲＡＣＴＩＯＮＫＩＮＥＴＩＣＳＯＦＲＡＲＥＥＡＲＴＨ（Ⅰ）ＡＣｏｎｓｔａｎｔＩｎｔｅｒｆａｃｉａｌＣｅｌｌｗｉｔｈＬａｍｉｎａｒＦｌｏｗ￥ＺＨＥＮＧＺｈｏｎｇ；ＬＩＤｅｑｉａｎ（ＣｈａｎｇｃｈｕｎＩｎｓｔｉｔｕｔｅｏｆＡｐｐｌｉｅｄＣｈｅｍｉｓ...

关键词： constant inter face cell laminar flow kinetics mass transfer

Numerical Simulation of laminar flow Field in a Stirred Tank

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Chinese Journal of Chemical Engineering 2004年第3期12卷 324-329页

作者：范茏王卫京杨超毛在砂 Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 China Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 Chinatirred tanks are used extensively in process industry and one of the most commonly used impellers in stirred tanks is the Rushton disk turbine. Surprisingly few data are available regarding flow and mixing in stirred-tank reactors with Rushton turbine in the laminar regime in particular the laminar flow in baffled tanks. In this paper the laminar flow field in a baffled tank stirred by a standard Rushton turbine is simulated with the improved inner-outer iterative method. The non-inertial coordinate system is used for the impeller region which is in turn used as the boundary conditions for iteration. It is found that the simulation results are in good agreement with previous experiments. In addition the flow number and impeller power number calculated from the simulated flow field are in satisfactory agreement with experimental data. This numerical method allows prediction of flow structure requiring no experimental data as the boundary conditions and has the potential of being used to scale-up and design of related process equipment.

Stirred tanks are used extensively in process industry and one of the most commonly used impellers in stirred tanks is the *** disk turbine. Surprisingly few data are available regarding flow and mixing in stirred-tank reactors with Rushton turbine in the laminar regime, in particular the laminar flow in baffled *** this paper, the laminar flow field in a baffled tank stirred by a standard *** turbine is simulated with the improved inner-outer iterative method. The non-inertial coordinate system is used for the impeller region, which is in turn used as the boundary conditions for iteration. It is found that the simulation results are in good agreement with previous experiments. In addition, the flow number and impeller power number calculated from the simulated flow field are in satisfactory agreement with experimental data. This numerical method allows prediction of flow structure requiring no experimental data as the boundary conditions and has the potential of being used to scale-up and design of related process equipment.

关键词： numerical simulation laminar flow stirred tank Rushton turbine