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Applied Mathematics and Mechanics(English Edition) 2022年第12期43卷 1951-1964页

作者： B.J.GIREESHA L.ANITHA Department of Post Graduation Studies and Research in Mathematics Kuvempu UniversityShankaraghatta 577451India Department of Mathematics Adichunchanagiri Institute of TechnologyChikkamagaluru 577102India

The main aim of the present work is to investigate the flow and heat transport properties of non-Newtonian Casson-Williamson fluid through an upright microchannel along with entropy generation analysis,and explore the effects of convective boundary conditions,Couette-Poiseuille flow,and nonlinear radiation.The movement of liquid is scrutinized with the Hall effect and exponential heat source.The rheological characteristics of the Casson-Williamson fluid model are also considered.By considering the desirable similarity variables,the equations of motion are reduced to nonlinear ordinary differential equations.The Runge-Kutta-Fehlberg fourth-fifth order method along with the shooting method is adopted to solve these dimensionless expressions.The detailed investigation is pictorially displayed to show the influence of effective parameters on the entropy generation and the bejan number.One of the major tasks of the exploration is to compare the Casson fluid and the Williamson fluid.The results show that the rate of heat transfer in the Casson fluid is more remarkable than that in the Williamson fluid.

关键词： entropy generation bejan number convective boundary condition Hall effect nonlinear radiation exponential heat source

First and second laws analysis of viscoelastic fluid with temperature dependent properties for Couette-Poiseuille flow

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Propulsion and Power Research 2023年第3期12卷 380-396页

作者： Mehdi Moayed Mohseni Farshid Pajoum Shariati Department of Chemical Engineering Science and Research BranchIslamic Azad UniversityTehran 14778-93855Iran

The entropy analysis of viscoelastic fluid obeying the simplified Phan-ThienTanner(SPTT)model with variable thermophysical properties are obtained for laminar,steady state and fully developed Couette-Poiseuille flow.The homotopy perturbation method(HPM)allows us to solve nonlinear momentum and energy differential equations.The Reynold’s model is used to describe the temperature dependency of thermophysical properties.Results indicate that the increase of the group parameter(Br=U)and the Brinkman number(Br)which show the power of viscous dissipation effect;increases the entropy generation while increasing fluid elasticity(εDe2)decreases the generated entropy.Increasing the Reynolds variational parameter(a)which control the level of temperature dependence of physical properties attenuate entropy generation when moving plate and applied pressure gradient have the opposite direction and decreases entropy generation when moving plate and applied pressure gradient have the same direction or both plates are at rest.Also,increasing elasticity reduces the difference between variable and constant thermophysical properties cases.These results may give guidelines for cost optimization in industrial processes.

关键词： Entropy analysis Homotopy perturbation method(HPM) Viscoelastic simplified Phan-Thien-Tanner(SPTT)model Temperature dependent properties Reynold’s model bejan number

Physical aspects of magnetized Jeffrey nanomaterial flow with irreversibility analysis

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Chinese Physics B 2022年第8期31卷 485-493页

作者： Fazal Haq Muhammad Ijaz Khan Sami Ullah Khan Khadijah M Abualnaja M A El-Shorbagy Department of Mathematics Karakoram International University Main CampusGilgit 15100Pakistan Department of Mathematics and Statistics Riphah International University I-14Islamabad 44000Pakistan Department of Mechanics and Engineering Science Peking UniversityBeijing 100871China Department of Mathematics COMSATS University IslamabadSahiwal 57000Pakistan Department of Mathematics and Statistics College of ScienceTaif UniversityP.O.Box 11099Taif 21944Saudi Arabia Department of Mathematics College of Science and Humanities in Al-KharjPrince Sattam bin Abdulaziz UniversityAl-Kharj 11942Saudi Arabia Department of Basic Engineering Science Faculty of EngineeringMenoufia UniversityShebin El-Kom 32511Egypt

This research presents the applications of entropy generation phenomenon in incompressible flow of Jeffrey nanofluid in the presence of distinct thermal features. The novel aspects of various features, such as Joule heating, porous medium,dissipation features, and radiative mechanism are addressed. In order to improve thermal transportation systems based on nanomaterials, convective boundary conditions are introduced. The thermal viscoelastic nanofluid model is expressed in terms of differential equations. The problem is presented via nonlinear differential equations for which analytical expressions are obtained by using the homotopy analysis method(HAM). The accuracy of solution is ensured. The effective outcomes of all physical parameters associated with the flow model are carefully examined and underlined through various curves. The observations summarized from current analysis reveal that the presence of a permeability parameter offers resistance to the flow. A monotonic decrement in local Nusselt number is noted with Hartmann number and Prandtl number.Moreover, entropy generation and bejan number increases with radiation parameter and fluid parameter.

关键词： Jeffrey nonmaterial entropy generation magnetohydrodynamics(MHD) bejan number porous medium Brownian motion

Irreversibility investigation of Casson fluid flow in an inclined channel subject to a Darcy-Forchheimer porous medium:a numerical study

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Applied Mathematics and Mechanics(English Edition) 2021年第1期42卷 95-108页

作者： A.ROJA B.J.GIREESHA B.NAGARAJA Department of PG Studies and Research in Mathematics Kuvempu UniversityShankaraghattaShimoga 577451KarnatakaIndia

The heat transfer and entropy generation characteristics of the magnetohydrodynamic Casson fluid flow through an inclined microchannel with convective boundary conditions are analyzed.Further,the effects of the viscous forces,Joule heating,heat source/sink,and radiation on the flow are taken into account.The non-dimensional transformations are used to solve the governing equations.Then,the reduced system is resolved by the fourth-fifth order Runge-Kutta-Fehlberg method along with the shooting technique.The effects of different physical parameters on the heat transfer and entropy generation are discussed in detail through graphs.From the perspective of numerical results,it is recognized that the production of entropy can be improved with the Joule heating,viscous dissipation,and convective heating aspects.It is concluded that the production of entropy is the maximum with increases in the Casson parameter,the angle of inclination,and the Hartmann number.Both the Reynolds number and the radiation parameter cause the dual impact on entropy generation.

关键词： inclined channel Casson fluid magnetism radiation entropy generation bejan number

Analytical approach to entropy generation and heat transfer in CNT-nanofluid dynamics through a ciliated porous medium

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Journal of Hydrodynamics 2018年第2期30卷 296-306页

作者： Noreen Sher Akbar M.Shoaib Dharmendra Tripathi Shashi Bhushan O.Anwar Bég DBS&H CEME National University of Sciences and Technology School of Natural Sciences National University of Sciences and Technology Department of Mechanical Engineering Manipal University Medical Energy and Propulsion Engineering Sciences Department of Aeronautical and Mechanical Engineering University of Salford

The transportation of biological and industrial nanofluids by natural propulsion like cilia movement and self-generated contraction-relaxation of flexible walls has significant applications in numerous emerging technologies. Inspired by multi-disciplinary progress and innovation in this direction, a thermo-fluid mechanical model is proposed to study the entropy generation and convective heat transfer of nanofluids fabricated by the dispersion of single-wall carbon nanotubes（SWCNT） nanoparticles in water as the base fluid. The regime studied comprises heat transfer and steady, viscous, incompressible flow, induced by metachronal wave propulsion due to beating cilia, through a cylindrical tube containing a sparse（i.e., high permeability） homogenous porous medium. The flow is of the creeping type and is restricted under the low Reynolds number and long wavelength approximations. Slip effects at the wall are incorporated and the generalized Darcy drag-force model is utilized to mimic porous media effects. Cilia boundary conditions for velocity components are employed to determine analytical solutions to the resulting non-dimensionalized boundary value problem. The influence of pertinent physical parameters on temperature, axial velocity, pressure rise and pressure gradient, entropy generation function, bejan number and stream-line distributions are computed numerically. A comparative study between SWCNT-nanofluids and pure water is also computed. The computations demonstrate that axial flow is accelerated with increasing slip parameter and Darcy number and is greater for SWCNT-nanofluids than for pure water. Furthermore the size of the bolus for SWCNT-nanofluids is larger than that of the pure water. The study is applicable in designing and fabricating nanoscale and microfluidics devices, artificial cilia and biomimetic micro-pumps.

关键词： Metachronal wave single-wall carbon nanotubes （SWCNT） entropy generation porous medium cilia motion heat transfer bejan number

Regular perturbation solution of Couette flow(non-Newtonian)between two parallel porous plates: a numerical analysis with irreversibility

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Applied Mathematics and Mechanics(English Edition) 2021年第1期42卷 127-142页

作者： M.NAZEER M.I.KHAN S.KADRY Yuming CHU F.AHMAD W.ALI M.IRFAN M.SHAHEEN Department of Mathematics Institute of Arts and SciencesGovernment College UniversityChiniot CampusFaisalabad 35400Pakistan Department of Mathematics and Statistics Riphah International University I-14Islamabad 44000Pakistan Department of Mathematics and Computer Science Beirut Arab UniversityBeirut 11-5020Lebanon Department of Mathematics Huzhou UniversityHuzhou 313000Zhejiang ProvinceChina Hunan Provincial Key Laboratory of Mathematical Modeling and Analysis in Engineering Changsha University of Science&TechnologyChangsha 410114China Department of Applied Sciences National Textile UniversityFaisalabad 38000Pakistan Chair of Production Technology Faculty of Engineering TechnologyUniversity of TwenteEnschede 7500 AEThe Netherlands Department of Mathematics Riphah Inernational LniversityFaisalabad CampusFaiselabad 38000Pakistan

The unavailability of wasted energy due to the irreversibility in the process is called the entropy generation.An irreversible process is a process in which the entropy of the system is increased.The second law of thermodynamics is used to define whether the given system is reversible or irreversible.Here,our focus is how to reduce the entropy of the system and maximize the capability of the system.There are many methods for maximizing the capacity of heat transport.The constant pressure gradient or motion of the wall can be used to increase the heat transfer rate and minimize the entropy.The objective of this study is to analyze the heat and mass transfer of an Eyring-Powell fluid in a porous channel.For this,we choose two different fluid models,namely,the plane and generalized Couette flows.The flow is generated in the channel due to a pressure gradient or with the moving of the upper lid.The present analysis shows the effects of the fluid parameters on the velocity,the temperature,the entropy generation,and the bejan number.The nonlinear boundary value problem of the flow problem is solved with the help of the regular perturbation method.To validate the perturbation solution,a numerical solution is also obtained with the help of the built-in command NDSolve of MATHEMATICA 11.0.The velocity profile shows the shear thickening behavior via first-order Eyring-Powell parameters.It is also observed that the profile of the bejan number has a decreasing trend against the Brinkman number.Whenηi→0(i=1,2,3),the Eyring-Powell fluid is transformed into a Newtonian fluid.

关键词： Couette flow Eyring-Powell fluid entropy generation perturbation method bejan number

Entropy analysis of unsteady magneto-nanofluid flow past accelerating stretching sheet with convective boundary condition

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Applied Mathematics and Mechanics(English Edition) 2015年第12期36卷 1593-1610页

作者： S.DAS S.CHAKRABORTY R.N.JANA O.D.MAKINDE Department of Mathematics University of Gour Banga Department of Applied Mathematics Vidyasagar University Faculty of Military Science Stellenbosch University

The unsteady laminar magnetohydrodynamics （MHD） boundary layer flow and heat transfer of nanofluids over an accelerating convectively heated stretching sheet are numerically studied in the presence of a transverse magnetic field with heat source/sink The unsteady governing equations are solved by a shooting method with the Runge-Kutta- Fehlberg scheme. Three different types of water based nanofluids, containing copper, aluminium oxide, and titanium dioxide, are taken into consideration. The effects of the pertinent parameters on the fluid velocity, the temperature, the entropy generation num- ber, the bejan number, the shear stress, and the heat transfer rate at the sheet surface are graphically and quantitatively discussed in detail. A comparison of the entropy generation due to the heat transfer and the fluid friction is made with the help of the bejan number. It is observed that the presence of the metallic nanoparticles creates more entropy in the nanofluid flow than in the regular fluid flow.

关键词： unsteady MHD flow nanofluid heat source/sink entropy generation bejan number