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non-newtonian effect on natural convection flow over cylinder of elliptic cross section

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Applied Mathematics and Mechanics(English Edition) 2020年第2期41卷 361-382页

作者： P.NAG M.M.MOLLA M.A.HOSSAIN Department of Mathematics and Physics North South UniversityDhaka 1229Bangladesh Center for Applied Scientific Computing(CASC) North South UniversityDhaka 1229Bangladesh Department of Mathematics University of DhakaDhaka 1000Bangladesh

The non-newtonian effect in the boundary layer flow over a horizontal elliptical cylinder is investigated numerically. A modified power-law viscosity model is used to correlate the non-newtonian characteristics of the fluid flow. For natural convectionflows, the surface of the cylinder is maintained by the uniform surface temperature(UST)or the uniform heat flux(UHF) condition. The governing equations corresponding to theflow are first transformed into a dimensionless non-similar form using suitable transformations. The resulting equations are solved numerically by an efficient finite difference scheme. The numerical results are presented for the skin friction coefficient and the local Nusselt number with the eccentric angle for different values of the power-law index n. The local skin friction coefficient and the local Nusselt number are found to be higher and lower, respectively, for the shear thickening fluids(n > 1) than the other fluids(n≤1).The effects of different elliptical configurations on the average Nusselt number are also presented and discussed for both conditions of the surface temperature.

关键词： non-newtonian fluid free convection boundary layer elliptical cylinder

non-newtonian steady shear flow characteristics of waxy crude oil

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Journal of Central South University 2008年第S1期15卷 326-328页

作者：黄树新陈鑫鲁传敬侯磊范毓润 Department of Engineering Mechanics Shanghai Jiaotong University Department of Petroleum Storage and Transportation China University of Petroleum State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

The experimental research on the non-newtonian flow characteristic of a waxy crude oil was conducted through a rotational parallel-plates rheometer *** test temperature is about 6.5 ℃ higher than its gel *** shear stress and viscosity of the waxy crude oil show sophisticate non-newtonian characteristics in the shear rate of 10-4-102 s-1,in which the shear stress can be divided into three parts qualitatively,***-up region,leveling-off region,and stress-up *** indicates that there is a yielding process in shearing for the waxy crude oil at the experimental temperature,which is similar to the yield phenomenon in thixotropy-loop test discussed by CHANG and ***,the steady shear experiment after the pre-shear process shows that the stress leveling-off region at low shear rate disappears for the waxy crude oil and the stress curve becomes a monotonic climbing one,which demonstrates that the internal structure property presenting through yielding stress at low shear rate can be changed by *** experimental results also show that the internal structure of waxy crude oil presenting at low shear rate has no influence on the shear viscosity obtained at the shear rate higher than 0.1 *** generalized newtonian model is adopted to describe the shear-thinning viscosity property of the waxy crude oil at high shear rate.

关键词： waxy crude oil shear flow non-newtonian flow generalized newtonian model

Study on non-newtonian Behaviors of Lennard-Jones Fluids via Molecular Dynamics Simulations

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Chinese Journal of Chemical Physics 2016年第6期29卷 754-760,I0002页

作者： Ruo-yu Dong Bing-yang Cao He-ming Yun Bao-ming Chen KeyLaboratoryofRenewableEnergyUtilizationTechnologiesinBuildingofMinistryofEducation ShandongJianzhuUniversityJinan250101China KeyLaboratoryforThermalScienceandPowerEngineeringofMinistryofEducation DepartmentofEngineeringMechanicsTsinghuaUniversityBeijing100084China

Using nonequilibrium molecular dynamics simulations, we study the non-newtonian rhe-ological behaviors of a monoatomic fluid governed by the Lennard-Jones potential. Both steady Couette and oscillatory shear flows are investigated. Shear thinning and normal stress effects are observed in the steady Couette flow simulations. The radial distribution function is calculated at different shear rates to exhibit the change of the microscopic struc- ture of molecules due to shear. We observe that for a larger shear rate the repulsion between molecules is more powerful while the attraction is weaker, and the above phenomena can also be confirmed by the analyses of the potential energy. By applying an oscillatory shear to the system, several findings are worth mentioning here： First, the phase difference between the shear stress and shear rate increases with the frequency. Second, the real part of complex viscosity first increases and then decreases while the imaginary part tends to increase mono- tonically, which results in the increase of the proportion of the imaginary part to the real part with the increasing frequency. Third, the ratio of the elastic modulus to the viscous modulus also increases with the frequency. These phenomena all indicate the appearance of viscoelasticity and the domination of elasticity over viscosity at high oscillation frequency for Lennard-Jones fluids.

关键词： non-newtonian Viscoelasticity Lennard-Jones fluids Molecular dynamics

MASS TRANSFER AND HYDRODYNAMICS IN AN AIRLIFT REACTOR WITH VISCOUS non-newtonian FLUID

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Chinese Journal of Chemical Engineering 1995年第1期3卷 26-34页

作者：李国庆杨守志蔡昭铃陈家镛中科院化工冶金所北京

In an internal loop airlift reactor of 55L working volume,the gas-liquid volumetric oxygenmass transfer coefficient k_Lα,gas holdup ε_G and liquid circulation time t_c were measured with the sol-ution of carboxymethyl cellulose(CMC)to simulate the performance of a reactor with highly *** conductivity and oxygen probes were used to measure the local gas holdup,liquidcirculation time and oxygen mass transfer coefficient in the individual sections of the reactor(riser,downcomer and the gas-liquid separating section at the top of the reactor)and the total reactor,*** values of k_Lα for the riser,downcomer and separation sections of the reactor were alsoestimated and compared with that for the total *** results show that,both k_Lα and ε_G in-crease but t_c decreases with increasing gas *** and comparisons with works reportedin the literature are also *** show that the methods developed for k_Lα measurements inthe individual section

关键词： oxygen mass transfer airlift reactor non-newtonian fluid high-viscous fluid

HEAT TRANSFER STUDIES OF HIGHLY VISCOUS non-newtonian FLUIDS IN VERTICAL TUBES BY FINITE ELEMENT METHOD

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Chinese Journal of Chemical Engineering 1996年第1期4卷 65-74页

作者：钱夕元侯望奇江体乾华东理工大学化学工程系上海

A numerical method capable is developed for handling steady laminar flow and heat trans-fer of a highly viscous power-law fluid whose density,viscosity,specific heat and thermalconductivity,vary with *** governing equations are found to be continuity,monmentumand energy *** effects such as varying viscosity,natural convection and viscousdissipation are incorporated in the theoretical *** equations are being attracted by employing a decoupled finite element ***’sprinciple is used to handle the momentum and continuity ***(SU/PG)andnon-consistent(SU)streamline upwind methods are employed for the energy *** calculated results and experimental data shows good *** results are obtained withSU and SU/PG *** and temperature profiles which provide insights into the processare also given.

关键词： non-newtonian fluids vertical tube finite clement method

ANALYSIS OF DRAWING UNDER LUBRICATION OF non-newtonian LUBRICATING MATERIALS

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中国有色金属学会会刊：英文版 1995年第4期5卷 173-176页

作者： Lei Zhanbo Wang Zhanxue Gao Youzhi(Department of Mechanical Engineering,Tsinghua University,Beijing 100084)(Department of Metal Processing, Northeastern University,Shenyang 110006) Tsinghua Univ Beijing China

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关键词： drawing force rheology upper-bound method non-newtonian material tribology

Thermal Analysis of MHD non-newtonian Nanofluids over a Porous Media

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Computer Modeling in Engineering & Sciences 2020年第12期125卷 1119-1134页

作者： Asad Ejaz Imran Abbas Yasir Nawaz Muhammad Shoaib Arif Wasfi Shatanawi Javeria Nawaz Abbasi Stochastic Analysis&Optimization Research Group Department of MathematicsAir UniversityIslamabad44000Pakistan Department of Mathematics and General Sciences Prince Sultan UniversityRiyadh11586Saudi Arabia Department of Medical Research China Medical University HospitalChina Medical UniversityTaichung40402TaiwanChina Department of Mathematics Hashemite UniversityZarqa13116Jordan Department of Mathematics Comsats UniversityIslamabad44000Pakistan

In the present research,Tiwari and Das model are used for the impact of a magnetic field on non-newtonian nanofluid flow in the presence of injection and *** PDEs are converted into ordinary differential equations(ODEs)using the similarity *** obtained ordinary differential equations are solved numerically using shooting method along with *** of the present study uses nanoparticles(NPs)like TiO_(2) andAl_(2)O_(3) and sodium carboxymethyl cellulose(CMC/water)is considered as a base fluid(BF).This study is conducted to find the influence of nanoparticles,Prandtl number,and magnetic field on velocity and temperature profile,however,the Nusselt number and coefficient of skin friction parameters are also presented in detail with the variation of nanoparticles and *** obtained results of the present study are presented *** addition to these,some simulations of partial differential equations are also shown using software for graphing surface plots of velocity profile and streamlines along with surface plots and isothermal contours of the temperature profile.

关键词： MHD non-newtonian nanofluids porous medium similarity solution Blasius flow

Boundary-layer non-newtonian flow over vertical plate in porous medium saturated with nanofluid

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Applied Mathematics and Mechanics(English Edition) 2011年第12期32卷 1577-1586页

作者： F.M. HADY F. S. IBRAHIM S. M. ABDEL-GAIED M. R. EID Department of Mathematics Faculty of Science Assiut University Assiut 71516 Egypt Department of Science and Mathematics Faculty of Education Assiut University The New Valley 72111 Egypt

The free convective heat transfer to the power-law non-newtonian flow from a vertical plate in a porous medium saturated with nanofluid under laminar conditions is investigated. It is considered that the non-newtonian nanofluid obeys the mathematical model of power-law. The model used for the nanofluid incorporates the effects of Brown- ian motion and thermophoresis. The partial differential system governing the problem is transformed into an ordinary system via a usual similarity transformation. The numer- ical solutions of the resulting ordinary system are obtained. These solutions depend on the power-law index n, Lewis number Le, buoyancy-ratio number Nr, Brownian motion number Nb, and thermophoresis number Nt. For various values of n and Le, the effects of the influence parameters on the fluid behavior as well as the reduced Nusselt number are presented and discussed.

关键词： non-newtonian free convection nanofluid porous media

The Strong Solution for the Viscous Polytropic Fluids with non-newtonian Potential

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Chinese Annals of Mathematics,Series B 2019年第2期40卷 237-250页

作者： Qiu MENG Hongjun YUAN Institute of Mathematics and Statistics Beihua University Institute of Mathematics Jilin University

The authors study an initial boundary value problem for the three-dimensional Navier-Stokes equations of viscous heat-conductive fluids with non-newtonian potential in a bounded smooth domain. They prove the existence of unique local strong solutions for all initial data satisfying some compatibility conditions. The difficult of this type model is mainly that the equations are coupled with elliptic, parabolic and hyperbolic, and the vacuum of density causes also much trouble, that is, the initial density need not be positive and may vanish in an open set.

关键词： Compressible Navier-Stokes equations Viscous polytropic fluids Vacuum Poincare type inequality non-newtonian potential