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Applied Mathematics and Mechanics(English Edition) 2016年第4期37卷 433-442页

作者： Limei CAO xinhui si Liancun ZHENG Department of Applied Mathematics School of Mathematics and PhysicsUniversity of Science and Technology Beijing

The convection of a Maxwell fluid over a stretching porous surface with a heat source/sink in the presence of nanoparticles is investigated. The Lie symmetry group transformations are used to convert the boundary layer equations into coupled nonlinear ordinary differential equations. The ordinary differential equations are solved numerically by the Bvp4c with MATLAB, which is a collocation method equivalent to the fourth-order mono-implicit Runge-Kutta method. Furthermore, more attention is paid to the effects of the physical parameters, especially the parameters related to nanoparticles, on the temperature and concentration distributions with consideration of permeability and the heat source/sink.

关键词： Lie group Maxwell fluid porous stretching surface heat sink or source

Non-Newtonian biomagnetic fluid flow through a stenosed bifurcated artery with a slip boundary condition

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Applied Mathematics and Mechanics(English Edition) 2020年第11期41卷 1611-1630页

作者： Yaxin XU Jing ZHU Liancun ZHENG xinhui si School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China

The effects of a velocity slip and an external magnetic field on the flow of biomagnetic fluid(blood)through a stenosed bifurcated artery are investigated by using ANSYS *** is regarded as a non-Newtonian power-law fluid,and the magnetization and electrical conductivity are considered in the mathematical *** no-slip condition is replaced by the first-order slip *** slip boundary condition and magnetic force are compiled in the solver by the user-defined function(UDF).Numerical solutions are obtained by the finite volume method based on a nonuniform grid *** accuracy and efficiency of the solver are verified through a comparison with the *** results are presented graphically for different parameter values,and the effects of the magnetic number,the magnetic source position,the vascular obstruction ratio,the slip parameter,and the power-law index on the flow and temperature fields are illustrated.

关键词： power-law fluid biomagnetic fluid magnetic field velocity slip stenosed bifurcated artery

Effects of nonlinear velocity slip and temperature jump onpseudo-plastic power-law fluid over moving permeable surface in presence of magnetic field

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Applied Mathematics and Mechanics(English Edition) 2017年第3期38卷 333-342页

作者： xinhui si Haozhe LI Yanan SHEN Liancun ZHENG School of Mathematics and Physics University of Science and Technology Beijing Beijing 100083 China

Flow and heat transfer of a pseudo-plastic power-law fluid over a stretching permeable surface with the magnetic effect is investigated. In the boundary conditions,the nonlinear temperature jump and the velocity slip are considered. Semi-similarity equations are obtained and solved by bvp4c with MATLAB. The problem can be considered as an extension of the previous work done by Mahmoud(Mahmoud, M. A. A. Slip velocity effect on a non-Newtonian power-law fluid over a moving permeable surface with heat generation. Mathematical and Computer Modelling, 54, 1228–1237(2011)). Efforts are made to discuss the effects of the power-law number, slip velocity, and temperature jump on the dimensionless velocity and temperature distribution.

关键词： power-law fluid varying thermal conductivity slip velocity temperature jump magnetohydrodynamic (MHD)

A Study of Multiple Solutions for the Navier-Stokes Equations by a Finite Element Method

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Numerical Mathematics(Theory,Methods and Applications) 2014年第1期7卷 107-122页

作者： Huanxia Xu Ping Lin xinhui si Department of Mathematics and Mechanics University of Science and Technology BeijingBeijing 100083China Department of Mathematics University of DundeeDundee DD14HNUK.

In this paper,a finite element method is proposed to investigate multiple solutions of the Navier-Stokes equations for an unsteady,laminar,incompressible flow in a porous expanding *** or triple solutions for the fixed values of the wall suction Reynolds number R and the expansion ratioαare obtained *** computed multiple solutions for the symmetric flow are validated by comparing them with approximate analytic solutions obtained by the similarity transformation and homotopy analysis *** previous works,our method deals with the Navier-Stokes equations directly and thus has no similarity and other restrictions as in previous *** we use the method to study multiple solutions for three cases of the asymmetric flow(which has not been studied before using the similarity-type techniques).

关键词： Finite element method Navier-Stokes equations porous channel expanding walls

On the process of filtration of fractional viscoelastic liquid food

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Communications in Theoretical Physics 2021年第4期73卷 29-44页

作者： Yahui Meng Botong Li xinhui si Xuehui Chen Fawang Liu School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China School of Mathematical Sciences Queensland University of TechnologyGPO Box 2434BrisbaneQld.4001Australia

In the process of filtration,fluid impurities precipitate/accumulate;this results in an uneven inner wall of the filter,consequently leading to non-uniform suction/*** Riemannian-Liouville fractional derivative model is used to investigate viscoelastic incompressible liquid food flowing through a permeable plate and to generalize Fick's ***,we consider steady-state mass balance during ultrafiltration on a plate surface,and a fractional-order concentration boundary condition is established,thereby rendering the problem real and *** governing equation is numerically solved using the finite difference *** effects of the fractional constitutive models,generalized Reynolds number,generalized Schmidt number,and permeability parameter on the velocity and concentration fields are *** results show that an increase in fractional-orderαin the momentum equation leads to a decrease in the horizontal *** diffusion described by the fractional derivative model weakens the mass transfer;therefore,the concentration decreases with increasing fractional derivativeγin the concentration equation.

关键词： non-uniform permeable surface viscoelastic fluid fractional calculus implicit numerical method

The flow of the asymmetric couple stress fluid in a porous channel with expanding or contracting walls

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The flow of the asymmetric couple stress fluid in a porous c...

The laminar flow in a porous expanding tube

中国力学大会——2013

作者： si xinhui Zheng Liancun Department of Mathematics University of Sciences and Technology

In this paper,we investigate the asymetric flow of the couple stress fluid in a porous channel with expanding or contracting *** asymmetric injection or suction along the uniformly expanding porous walls and using suitable similar transformations,the governing equations are reduced to nonlinear ordinary *** analysis method is employed

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The laminar flow in a porous expanding tube

si-C Foam Porous-Medium Combustion Power-Generation System for Low-Calorific-Value Biomass Syngas

第七届全国流体力学学术会议

作者： si xinhui Li Lin Lin Ping Zheng Liancun University of Science and Technology Beijing

In the paper we numerically investigate multiple similarity solutions for the unsteady, incom-pressible laminar flow in a porous expanding or contracting *** governing equations are reduced to a singular 4th-order nonlinear boundary value problem by a suitable similarity *** design a combined boundary value(BV)/initial value(IV) method to obtain all the solutions *** observe that some values of the expansion ratio does not fundamentally change the multiple solutions pattern,and that the combined BV/IV method is indeed an effective tool for this laminar flow problem,or in particular,for the singular boundary value problem existing multiple solutions.

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Journal of Thermal Science 2025年第1期34卷 206-222页

作者： YANG Jianwen CHEN Wei CAO Bingwei LIU xinhui LI Hang College of Mechanical and Aerospace Engineering Jilin University School of Mechanical and Vehicle Engineering Changchun University

Syngas produced from the gasification of organic feedstocks from biomass is one of the clean and sustainable sources of *** advantages of simple access and renewability of biomass energy can meet the energy needs of temporary power *** study presents a biomass power-generation system for vehicular *** biomass and a free-piston Stirling engine generator（FPSEG） as the primary material and prime mover,respectively,biomass energy is converted into electricity by combusting the syngas to heat the *** and key parameter design for biomass gasification and thermoelectric conversion systems within a power generation system were performed.A porous medium area was constructed using si-C foam ceramics to obtain an energy-conversion experimental *** effects of bed height,porosity,porous-region diameter,and air-intake conditions on the power-generation performance were investigated,and optimisations were performed for the thermoelectric conversion *** rate of increase during FPSEG power generation first increased and then decreased with increasing bed height,peaking at a bed height of 40 *** increasing porous-region diameter accelerated FPSEG power generation,whereas porosity changes in the porous media did not significantly affect the rate of change during FPSEG power *** increasing air intake,the rate of increase during power generation first increased and then *** maximum change rate and the highest thermoelectric conversion efficiency of the power-generation system occurred at 9.5 m3/h and 6.5 m3/h（～45.1%）air intakes,*** the thermal inertia and combustion structure of the thermoelectric conversion system significantly increased the power-generation rate of the system,with 1.8 W/s being observed at a 9.7 m3/h air intake.

关键词： biomass combined heat and power (CHP) gasification porous media combustion power generation

变热导率的幂律流体在水平波面上的传热问题研究

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工程科学学报 2023年第11期45卷 1977-1984页

作者：刘芳芳张爱莉司新辉曹丽梅北京科技大学数理学院北京100083

根据泰勒展开式和边界层理论,推导了变热导率的Oswad-de Waele幂律流体沿水平波面上的边界层方程.假设热传导系数是依赖于温度梯度的幂律函数,构建了变热导率的能量方程模型.引入一系列变换,把变量量纲为一化和坐标变换,将原始问题转换... 详细信息

根据泰勒展开式和边界层理论,推导了变热导率的Oswad-de Waele幂律流体沿水平波面上的边界层方程.假设热传导系数是依赖于温度梯度的幂律函数,构建了变热导率的能量方程模型.引入一系列变换,把变量量纲为一化和坐标变换,将原始问题转换为偏微分方程组,并用Keller-box方法进行数值求解.讨论了某些参数如波幅与波长的比值、幂律指数以及广义普朗特数对壁面摩擦和流体传热的影响.计算结果显示:表面速度和压力梯度沿波面呈周期性变化,而且它们的变化周期与波面的变化周期完全一致.而对于壁面的摩擦系数和局部Nusselt数,在靠近零点的地方会有剧烈震荡,沿轴向会呈现波形分布状态,随着波长比率的增大而减小,且会随着振幅的增大,壁面摩擦系数也会震荡加剧.随着幂律指数的增加,局部Nusselt数呈现递减的分布状态.对于问题的特殊情况,当壁面是光滑平板时,尽管壁面的摩擦系数和局部Nusselt数沿轴向在初始位置会有波动,但会在很短的距离达到稳定的状态.从不同参数对周期的影响来看,周期性波动的壁面摩擦系数和局部Nusselt数与波面曲线的峰顶和波谷并不保持一致.

关键词：幂律流体正弦波面变热导率泰勒展式边界层理论

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不同几何形状的拱形支撑结构表面风压研究

Acta Mechanica sinica 2023年第7期39卷 122-140页

作者：范治汕李博通司新辉胡雅静朱婧 School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China

本文评估了拱形支撑结构周围的风流场特性,属于计算流体动力学的研究领域.通过与文献中风洞试验数据的对比,验证了数值模拟结果.本文不但给出了不同形状拱形支撑结构(尖顶、扁平和拱形结构)表面的平均、脉动、最大和最小风压系数,而且... 详细信息

本文评估了拱形支撑结构周围的风流场特性,属于计算流体动力学的研究领域.通过与文献中风洞试验数据的对比,验证了数值模拟结果.本文不但给出了不同形状拱形支撑结构(尖顶、扁平和拱形结构)表面的平均、脉动、最大和最小风压系数,而且讨论了不同的风向和结构高径比对风压系数的影响.结果表明,与其他结构相比,尖顶结构表面的风压系数和湍流扰动在数值上较低.地形粗糙度指数越低,结构表面的平均风压系数越大.此外,对于尖顶结构,高径比的增加会导致结构表面风压的增加.与其他风向相比,来风角度为45°的情况下屋顶表面所受负风压最强.值得指出的是,本文对于不同风向和尖顶结构的详细研究结果可以对工程设计优化领域有一定的借鉴意义.

关键词：风压系数拱形结构拱形支撑表面风压计算流体动力学几何形状高径比湍流扰动