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Journal of Central South University 2015年第8期22卷 3189-3201页

作者： K.Ramesh M.Devakar Department of Mathematics Visvesvaraya National Institute of Technology

The intention of this investigation is to study the effects of heat transfer and inclined magnetic field on the peristaltic flow of Williamson fluid in an asymmetric channel through porous medium. The governing two-dimensional equations are simplified under the assumption of long wavelength approximation. The simplified equations are solved for the stream function, temperature, and axial pressure gradient by using a regular perturbation method. The expression for pressure rise is computed numerically. The profiles of velocity, pressure gradient, temperature, heat transfer coefficient and stream function are sketched and interpreted for various embedded parameters and also the behavior of stream function for various wave forms is discussed through graphs. It is observed that the peristaltic velocity increases from porous medium to non-porous medium, the magnetic effects have increasing effect on the temperature, and the size of the trapped bolus decreases with the increasing of magnetic effects while the trend is reversed with the increasing of Darcy number. Moreover, limiting solutions of our problem are in close agreement with the corresponding results of the Newtonian fluid model.

关键词： Williamson fluid heat transfer inclined magnetic field porous medium inclined asymmetric channel

Theoretical investigation on submicron particle penetration through circular tubes inside a porous medium

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Particuology 2022年第11期70卷 55-63页

作者： Yanrong Yu Yongwei Gao Yanming Kang School of Environmental Science and Engineering Donghua UniversityShanghai 201620China School of Physics and Electronic-Electrical Engineering Ningxia UniversityYinchuan 750021China

The analytical infinite series solution of submicron particle transport in a circular tube bounded by a porous wall,such as a pinhole,is determined under the slip velocity boundary condition,and the solution is verified by using the experimental data in the previous studies for the specific *** results show that particle penetration rate increases with the increase of the porous parameter,the axial pressure drop,and the pinhole radius,whereas it decreases with increasing the pinhole *** penetration rate of nano-particles are more sensitive to the variation of these ***,the differences between the penetrations of particles ranging from 0.3μm to 1μm are not evident because the diffusion becomes weak gradually in this size *** addition,a further comparison is performed between the analytical solution and the existing studies,and approximate expressions are presented for accurate calculation of particle penetration rate through pinholes appearing in porous materials including filter devices and masks.

关键词： porous medium Penetration Submicron particle Circular tube Analytical solution

Numerical simulation of thermal convection of viscoelastic fluids in an open-top porous medium with constant heat flux

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Journal of Hydrodynamics 2015年第1期27卷 52-61页

作者：牛骏石在虹谭文长 Petroleum Exploration and Production Research Institute of SINOPEC State Key Laboratory for Turbulence and Complex Systems and Department of Mechanics and Aerospace Engineering College of Engineering Peking University

This paper makes a numerical study of the buoyancy-driven convection of a viscoelastic fluid saturated in an open-top porous square box under the constant heat flux boundary condition. The effects of the relaxation and retardation times on the onset of the oscillatory convection, the convection heat transfer rate and the flow pattern transition are investigated. It is shown that a large relaxation time can destabilize the fluid flow leading to an early onset of the thermal convection and a high heat transfer rate, while a large retardation time tends to stabilize the flow and suppress the convection onset and the heat transfer. After the convection sets in, the flow bifurcation appears earlier with the increase of the relaxation time and the decrease of the retardation time, resulting in more complicated flow patterns in the porous medium. Furthermore, with the increase of the ratio of the relaxation time to the retardation time, the fluid may be blocked from flowing through the open-top boundary, which may be caused by the viscoelastic effect. Finally, the comparison of our results with those under isothermal heating boundary conditions reveals that the heat transfer rate correspo- nding to a constant heat flux boundary is always higher.

关键词： thermal convection viscoelastic fluids porous medium constant heat flux

Effects of the porous medium and water-silver biological nanofluid on the performance of a newly designed heat sink by using first and second laws of thermodynamics

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Chinese Journal of Chemical Engineering 2020年第11期28卷 2928-2937页

作者： Amin Shahsavar Sajad Entezari Davood Toghraie Pouya Barnoon Department of Mechanical Engineering Kermanshah University of TechnologyKermanshahIran Department of Mechanical Engineering Khomeinishahr BranchIslamic Azad UniversityKhomeinishahrIran

The aim of this numerical investigation is to evaluate the laminar forced convection of biologically synthesized water-silver nanofluid through a heat sink(HS)filled with porous foam(PHS)using first and second laws of *** impacts of inlet velocity(V=0.5–3 m·s^-1)and volume fraction of nanofluid(φ=0–1%)on the performance metrics of HS are assessed and the outcomes are compared with those of the non-porous HS(NHS).The outcomes revealed that for both the PHS and NHS,the increase of V causes an intensification in convection coefficient,pumping power,and entropy generation due to fluid friction,while the maximum CPU temperature,thermal resistance,and entropy generation due to the heat transfer reduces by boosting ***,it was found that the augmentation of V results in intensification in convection coefficient,pumping power,overall hydrothermal performance,and frictional entropy generation,while the opposite is true for maximum CPU temperature,thermal resistance,and thermal entropy ***,it was reported that,except forφ=0.5%,the overall hydrothermal performance of NHS is better than that of PHS,while PHS has better second-law performance than NHS in all the studied ***,it can be concluded that the best hydrothermal performance for PHS belongs toφ=1%and V=0.5 m·s^-1,while for NHS,these values are 1%and 2 m·s^-1.

关键词： porous medium Heat sink First and second laws of thermodynamics Biologically prepared water-silver nanofluid

ON THE INTERACTION OF WATER WAVES AND SEABED BY THE porous medium MODEL

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Acta Mechanica Sinica 1995年第2期11卷 129-136页

作者：李家春林缅 Institute of Mechanics CAS Beijing China 100080

The interaction of water waves and seabed is studied by using Yamamoto's model, which takes into account the deformation of soil skeletal frame, compressibility of pore fluid flow as well as the Coulumb friction. When analyzing the propagation of three kinds of stress waves in seabed, a simplified dispersion relation and a specific damping formula are derived. The problem of seabed stability is further treated analytically based on the Mohr-Coulomb theory. The theory is finally applied to the coastal problems in the Lian-Yun Harbour and compared with observations and measurements in soil-wave tank with satisfactory results.

关键词： porous medium WAVE ATTENUATION COULOMB FRICTION SEABED STABILITY

Borehole guided waves in a non-Newtonian(Maxwell) fluid-saturated porous medium

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Chinese Physics B 2010年第8期19卷 442-448页

作者：崔志文刘金霞姚桂锦王克协 Department of Acoustics and Microwave Physics School of PhysicsJilin University The School of Communication Engineering Jilin University

The property of acoustic guided waves generated in a fluid-filled borehole surrounded by a non-Newtonian （Maxwell） fluid-saturated porous formation with a permeable wall is investigated. The influence of non-Newtonian effects on acoustic guided waves such as Stoneley waves, pseudo-Rayleigh waves, flexural waves, and screw waves propagations in a fluid-filled borehole is demonstrated based on the generalized Biot-Tsiklauri model by calculating their velocity dispersion and attenuation coefficients. The corresponding acoustic waveforms illustrate their properties in time domain. The results are also compared with those based on generalized Biot＇s theory. The results show that the influence of non-Newtonian effect on acoustic guided wave, especially on the attenuation coefficient of guided wave propagation in borehole is noticeable.

关键词： borehole guided waves Maxwell fluid porous medium

An In-Situ MRI Method for Quantifying Temperature Changes during Crystal Hydrate Growths in porous medium

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Journal of Thermal Science 2022年第5期31卷 1542-1550页

作者： ZHANG Lunxiang SUN Mingrui WANG Tian YANG Lei ZHANG Xiaotong ZHAO Jiafei SONG Yongchen Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education School of Energy and Power EngineeringDalian University of TechnologyDalian116024China Interdisciplinary Institute of Neuroscience and Technology Zhejiang UniversityHangzhou310029China

Given the complexity of the thermo-hydro-chemically coupled phase transition process of hydrates,real-time in-situ observations are *** maps are particularly essential in analyzing the heat transfer process during the growth and dissociation of crystal *** this study,we present the temporally and spatially resolved thermometry of the formation of tetrahydrofuran hydrates based on the temperature dependence of the chemical shift of the water *** of temperature changes were synchronously obtained using a 9.4 T^(1)H magnetic resonance imaging(MRI)system to predict the saturation level of the aqueous solution,phases of the solid hydrates,and the positive temperature anomaly of the exothermic *** was observed that variations in the MRI signal decreased while the temperature rise differed significantly in space and *** results predicted in this study could have significant implications in optimizing the phase transition process of gas hydrates.

关键词： hydrate phase transition heat transfer porous medium temperature mapping magnetic resonance imaging thermometry thermodynamics and molecular-scale phenomena

Effects of rotation and magnetic field on the nonlinear peristaltic flow of a second-order fluid in an asymmetric channel through a porous medium

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Chinese Physics B 2013年第7期22卷 303-313页

作者： A. M. Abd-Alla S. M. Abo-Dahab H. D. El-Shahrany Department of Mathematics Faculty of ScienceTaif University Department of Mathematics Faculty of Science Department of Mathematics Faculty of ScienceSouth Valley University

In this paper, the effects of both rotation and magnetic field of the peristaltic transport of a second-order fluid through a porous medium in a channel are studied analytically and computed numerically. The material is represented by the constitutive equations for a second-order fluid. Closed-form solutions under the consideration of long wavelength and low Reynolds number is presented. The analytical expressions for the pressure gradient, pressure rise, friction force, stream function, shear stress, and velocity are obtained in the physical domain. The effects of the non-dimensional wave amplitude, porosity, magnetic field, rotation, and the dimensionless time-mean flow in the wave frame are analyzed theoretically and computed numerically. Numerical results are given and illustrated graphically in each case considered. Comparison was made with the results obtained in the presence and absence of rotation, magnetic field, and porosity. The results indicate that the effects of the non-dimensional wave amplitude, porosity, magnetic field, rotation, and the dimensionless time-mean flow are very pronounced in the phenomena.

关键词： peristaltic flow second-order fluid magnetic field porous medium

MHD flow of nanofluids over an exponentially stretching sheet in a porous medium with convective boundary conditions

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Chinese Physics B 2014年第5期23卷 360-367页

作者： T.Hayat M.Imtiaz A.Alsaedi R.Mansoor Department of Mathematics Quaid-I-Azam University Department of Mathematics Faculty of ScienceKing Abdulaziz University

This article concentrates on the steady magnetohydrodynamic （MHD） flow of viscous nanofluid. The flow is caused by a permeable exponentially stretching surface. An incompressible fluid fills the porous space. A comparative study is made for the nanoparticles namely Copper （Cu）, Silver （Ag）, Alumina （A1203） and Titanium Oxide （TiO2）. Water is treated as a base fluid. Convective type boundary conditions are employed in modeling the heat transfer process. The non-linear partial differential equations governing the flow are reduced to an ordinary differential equation by similarity transformations. The obtained equations are then solved for the development of series solutions. Convergence of the obtained series solutions is explicitly discussed. The effects of different parameters on the velocity and temperature profiles are shown and analyzed through graphs.

关键词： MHD nanofluid exponentially stretching sheet porous medium convective boundary conditions

Neural Approach for Calculating Permeability of porous medium

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Chinese Physics Letters 2006年第4期23卷 1009-1011页

作者：张继成刘莉宋考平 Petroleum Engineering College Daqing Petroleum Institute Daqing Heilongjiang 163318 Institute of porous Plow and Fluid Mechanics China National Petroleum Corporation Langfang 065007

Permeability is one of the most important properties of porous media. It is considerably difficult to calculate reservoir permeability precisely by using single well-logging response and simple formula because reservoir is of serious heterogeneity, and well-logging response curves are badly affected by many complicated factors underground. We propose a neural network method to calculate permeability of porous media. By improving the algorithm of the back-propagation neural network, convergence speed is enhanced and better results can be achieved. A four-layer back-propagation network is constructed to effectively calculate permeability from well log data. Spontaneous potential, resistivity of deep lateral log, resistivity of micro-gradient log, resistivity of micro-normal log, Interval transit time of acoustic log and resistivity of shallow lateral log are selected as the inputs, and permeability is selected as the output. There are 35 and 40 units used in the two hidden layers, respectively. During the training course, the correlation coefficient between the calculated permeability and the standard pattern is as high as 0.9937, the average absolute error between them is 0.046μm^2 and the average relative error is only 1.93%. for practical applications, the average relative error between the calculated permeability and actual permeability is also as low as about 10.0%.

关键词： Neural Approach porous medium