Influence Of Viscous Dissipation Research Articles

Heat transfer enhancement in hydromagnetic dissipative flow past a moving wedge suspended by H2O-aluminum alloy nanoparticles in the presence of thermal radiation

This letter investigates the two dimensional magnetohydrodynamic Falkner Skan flow of water saturated with AA7072–H2O and AA7075–H2O nanoparticles over a moving wedge. Influence of viscous dissipation and thermal radiation is also under consideration. The model is reduced into nondimensional form by using defined self-similar transformations. Then, numerical study (Runge-Kutta numerical scheme) is carried out for solution purpose. The effects of pertinent flow parameters are discussed in the flow regimes by means of graphical aid. Graphical results for special cases (static wedge and when the movement of flow and wedge is in opposite direction) of the model are also elucidated graphically. It is noted that fluid velocity decreases for volumetric fraction and magnetic force favor the velocity. Significant effects of thermal radiation and nanoparticles volume fraction pointed for thermal filed and the influence of Eckert number is almost inconsequential. For more radiative fluid heat transfer coefficient decreases and nanoparticles volumetric fraction favor the local rate of heat transfer. In the presence of AA7075 nanoparticles, rate of heat transfer is quite rapid as compared to that of AA7072 nanoparticles. To validate the present computations, some present results are compared with already existing results in the literature and found better agreement between them. Finally, major points of the study ingrained in the last section of the letter.

Influence of viscous dissipation on a copper oxide nanofluid in an oblique channel: Implementation of the KKL model

This paper aims to study the flow of a nanofluid in the presence of viscous dissipation in an oblique channel (nonparallel plane walls). For thermal conductivity of the nanofluid, the KKL model is utilized. Water is taken as the base fluid and it is assumed to be containing the solid nanoparticles of copper oxide. The appropriate set of partial differential equations is transformed into a self-similar system with the help of feasible similarity transformations. The solution of the model is obtained analytically and to ensure the validity of analytical solutions, numerically one is also calculated. The homotopy analysis method (HAM) and the Runge-Kutta numerical method (coupled with shooting techniques) have been employed for the said purpose. The influence of the different flow parameters in the model on velocity, thermal field, skin friction coefficient and local rate of heat transfer has been discussed with the help of graphs. Furthermore, graphical comparison between the local rate of heat transfer in regular fluids and nanofluids has been made which shows that in case of nanofluids, heat transfer is rapid as compared to regular fluids.

Influence of viscous dissipation on unsteady MHD natural convective flow of Casson fluid over an oscillating vertical plate via FEM

Abstract In this paper, an unsteady magnetohydrodynamic natural convection, heat transfer, electrically conductive non-Newtonian Casson fluid over an oscillating vertical porous plate taken in to the account with an influence of viscous dissipation. An efficient computational Finite Element Method (FEM) employed to solve non-dimensional boundary layer partial differential equations for velocity and temperature distribution with the influence of emerging dimensionless parameters. Also, the local Skin-friction and local Nusselt number coefficients are obtained and analyzed through graphical and tabular forms. The results shows that increasing of Eckert number leads to increase in the velocity and temperature distribution while decrease in the local Skin-friction and Nusselt number coefficients. An increasing of Casson parameter leads to decrease in the velocity distribution and the local Skin-friction coefficient. Compared the present results with earlier reported studies of analytical solutions of Newtonian and non-Newtonian fluid flow problems. The current results are in excellent agreement with earlier existed results. The velocity and temperature distributions are closure for various mesh (grid) size. Therefore, these computational results are stable and converge. FEM is flexible and simplest method to solve this type of problems in various cases like Newtonian and non-Newtonian fluid flow problems.

Effect of thermal asymmetries on the entropy generation analysis of a variable viscosity Couette–Poiseuille flow

The influence of viscous dissipation on forced convective heat transfer and entropy generation rate in the conduction limit for a variable-viscosity flow between asymmetrically heated parallel plates is studied in an analytical framework consistent with perturbation method. The study considers a flow of Newtonian fluid under the simultaneous action of an applied pressure gradient and an axial movement of the upper plate. The present study emphasizes on the effect of dissipative heat produced by the movable upper plate as well as viscous heating generated due to applied pressure gradient on the underlying thermo-hydrodynamic transport. A few non-dimensional parameters such as dimensionless upper plate velocity, degree of asymmetry parameter and Brinkman number have been defined and their influential role on the variation of temperature profile, the Nusselt number and entropy generation number has been discussed in detail. The study shows that the variation of Nusselt number exhibits an unbounded swing, which, in turn, leads to appearance of the point of singularities at some cases of asymmetrical plate heating. Finally, the source of appearance of point of singularities has been discussed in view of the energy balance, and from the second-law analysis of thermodynamics.

Study of the Flow Response of a Chiral Fluid Confined in a Channel in the Presence of the Transverse Magnetic Field

The chiral materials are composed of the chiral molecules or inclusions which have ability to rotate electromagnetic waves or polarized light to a desired angle depending on chirality or handedness of the molecule or inclusions and the length of the medium. Fluids like sugar solution, sugar cane juice, turpentine and most of the body fluids etc are chiral. In recent years considerable attention has been given on the study of effect of chirality of molecules or inclusions on the propagation of electromagnetic waves through chiral medium, fabrication of chiral bio-interface materials, synthesis of chiral drug and chiral polymers. In this regard, present paper is intended to study the flow response of chiral fluid flowing in a vertical channel bounded by rigid permeable boundaries in the presence of applied transverse magnetic field under the influence of viscous dissipation, and convection electric current. The simplified and generalised non-linear momentum and energy equations governing the flow of a chiral fluid confined in a channel are solved for velocity and temperature for various values of dimensionless parameter analytically using the regular perturbation method with buoyancy parameter ‘N’ as perturbation parameter and numerically using finite difference method with Successive Over Relaxation (SOR) technique. The results obtained are depicted graphically and found that the resistance to flow of chiral fluid decreases with increase in the transverse magnetic field and the flow reversal occurs with change in the chirality parameter γ from -1 to 1

Influence of viscous dissipation and Joule heating on MHD bio-convection flow over a porous wedge in the presence of nanoparticles and gyrotactic microorganisms.

Background The flow over a porous wedge, in the presence of viscous dissipation and Joule heating, has been investigated. The wedge is assumed to be saturated with nanofluid containing gyrotactic microorganisms. For the flow, magneto-hydrodynamic effects are also taken into consideration. The problem is formulated by using the passive control model. The partial differential equations, governing the flow, are transformed into a set of ordinary differential equations by employing some suitable similarity transformations.ResultsA numerical scheme, called Runge–Kutta–Fehlberg method, has been used to obtain the local similarity solutions for the system. Variations in the velocity, temperature, concentration and motile micro-organisms density profiles are highlighted with the help of graphs. The expressions for skin friction coefficient, Nusselt number, Sherwood number and motile micro-organisms density number are obtained and plotted accordingly. For the validity of the obtained results, a comparison with already existing results (special cases) is also presented.ConclusionThe magnetic field increases the velocity of the fluid. Injection at the walls can be used to reduce the velocity boundary layer thickness. Thermal boundary layer thickness can be reduced by using the magnetic field and the suction at the wall. The motile microorganisms density profile is an increasing function of the bioconvection Pecket number and bioconvection constant. The same is a decreasing function of m, M and Le. The skin friction coefficient increases with increasing m and M . Nusselt number and the density number of motile microorganisms are higher for the case of suction as compared to the injection case. The density number of motile microorganisms is an increasing function for all the involved parameters.

Electromagnetohydrodynamic Flow and Heat Transfer of Nanofluid in a Parallel Plate Microchannel

AbstractThe present study is devoted to electromagnetohydrodynamic (EMHD) flow and heat transfer characteristics of nanofluid inside a parallel plate microchannel. The nanofluid is actuated by Lorentz force which is originated from the interaction of applied electrical field and perpendicular magnetic field. A fully developed assumption with uniform flux at the surface is considered in the analysis, and the influences of viscous dissipation as well as Joule heating are also taken into account. The analytical solutions for velocity and temperature are derived. Moreover, the Nusselt number variations are examined. The results show that the Hartmann number, the dimensionless parameter S and the nanoparticls volume fraction have significant influences on flow and temperature of nanofluid. As Hartmann number increasing, the Nusselt number improves and similar trend can be observed with the augment of nanoparticls volume fraction. A diminishment of heat transfer performance can be seen with increase of the Joule parameter and Brinkman number, while an enhancement in heat transfer can be witnessed with increase of nanoparticls volume fraction.

Mixed convection two-phase flow of Maxwell fluid under the influence of non-linear thermal radiation, non-uniform heat source/sink and fluid-particle suspension

Abstract A detailed investigation of two-dimensional mixed convection flow of non-Newtonian fluid due to convectively heated stretching sheet in the presence of dust particles is conducted. The influence of viscous dissipation, nonlinear thermal radiation and non-uniform heat source/sink is considered in the heat transport equation. To simulate the nonlinear thermal radiation effect, the Rosseland approximation has been used. The governing equations are transformed into a set of self-similar nonlinear ordinary differential equations by means of suitable similarity transformations, which are then solved numerically by using Shooting method. The influence of pertinent parameters on the velocity and temperature distributions of both fluid and particle phases inside the boundary layer is observed and discussed in detail. Further, the features of skin friction coefficient and Nusselt number for different values of the governing parameters are also analysed and discussed. Moreover, the numerical results of present study and those existing ones are tabulated for some limiting case.

Free convection in a square cavity filled by a porous medium saturated by a nanofluid: Viscous dissipation and radiation effects

The influence of the viscous dissipation and radiation effects on the natural convection heat transfer in a square cavity filled with porous media saturated with a nanofluid is studied. The vertical walls of the cavity are subject to finite temperature difference while the top and bottom walls of the cavity are insulated. The Buongiorno's nanofluid model, incorporating the Brownian motion and thermophoresis effects, is employed. The governing equations, in nondimensional form, are written in the weak form and solved using the finite element method. The influences of viscous dissipation and radiation effects on the concentration distribution of nanoparticles are discussed. The average and local Nusselt numbers are reported for various values of viscous dissipation (Eckert number) and radiation effects. The results show that the Nusselt numbers at the hot and cold walls are not equal due to the presence of viscous dissipation effects. The raise of Eckert number decreases the Nusselt number at hot wall, but it increases the Nusselt number at the cold wall. It is also found that the increase of Lewis number enhances the heat transfer in the cavity.

Heat transfer of nanofluids in microtubes under the effects of streaming potential

In the current study, the heat transfer characteristics of thermally developed electrokinetic flow of the nanofluid (water-Al2O3) through a microtube are investigated. The flow is actuated by the combined effects of pressure-driven and electroosmotic transport induced by streaming potential. A uniform flux at the surfaces of the microtube is exerted and the influences of viscous dissipation as well as Joule heating are taken into account. Based on the Debye–Hückel linearization approximation, the relevant velocity and temperature distributions are derived. Furthermore, Nusselt number variations are evaluated. Physical feathers of pertinent parameters such as electrokinetic width K, volume friction ϕ, slip lengthen γ, Brinkman number Br and Joule parameter S are presented graphically and discussed in detail. It is revealed that nanoparticles have significant influences on the electrokinetics and heat transfer characteristics of nanofluids under the streaming potential.

Influence of Viscous Dissipation on non‐Darcy Mixed Convection Flow of Nanofluid

In this paper, the steady fully developed non‐Darcy mixed convection flow of a nanofluid in a vertical channel filled with a porous medium with different viscous dissipation models is analyzed. The Brinkman‐Forchheimer extended Darcy model is used to describe the fluid flow pattern in the channel. The transport equations for a nanofluid are solved analytically using the seminumerical‐analytical method known as differential transformation method, and numerically with the Runge‐Kutta shooting method. Finally, the influence of pertinent parameters, such as solid volume fraction, different nanoparticles, mixed convection parameter, Brinkman number, Darcy number, and inertial parameter on the velocity and temperature fields are shown graphically. The results show that velocity and temperature are enhanced when the mixed convection parameter, Brinkman number, and Darcy number increases whereas solid volume fraction and inertial parameter decreases the velocity and temperature fields. The obtained results show that the nanofluid enhances the heat transfer process significantly.

Heat Transfer and Entropy Generation Analysis of Bingham Plastic Fluids in Circular Microchannels

The thermal characteristics of Bingham plastic fluid flows are analyzed in circular microchannels under uniform wall heat flux condition. The analytic approach presented here reveals that the governing parameters are Bingham number, dimensionless radius of the plug flow region, and Brinkman number. The results demonstrate that there is a strong influence of viscous dissipation on heat transfer and entropy generation for Brinkman numbers greater than a specific value. With increasing the Brinkman number and dimensionless radius of the plug flow region, entropy generation is increased, while the Nusselt number is decreased. The influence of these parameters on the entropy generation from heat transfer is strongly higher than the entropy generation from fluid friction. The average dimensionless total entropy shows that the Bingham plastic fluids generate entropy more than Newtonian fluids; also, an increase in the dimensionless radius of the plug flow region results in increasing the average dimensionless total entropy generation. By letting the dimensionless radius of the plug flow region equal to zero, the generalized expressions and results will be simplified to Newtonian fluids.

Influence of Viscous Dissipation on Free Non-Linear Convection with Soret Effects in a Porous Medium Saturated by Nanofluid

Influence of Viscous Dissipation on Free Non-Linear Convection with Soret Effects in a Porous Medium Saturated by Nanofluid

The influence of viscous dissipation on the unsteady conjugate forced convection heat transfer from a fluid sphere

The unsteady, conjugate, forced convection heat transfer from a fluid sphere to a surrounding fluid flow in the presence of viscous dissipation has been analysed. The fluid flow inside and outside the sphere was considered laminar, axisymmetric, steady and incompressible. The heat balance equations were solved numerically in spherical coordinates system by a splitting finite difference method. The influence of the Reynolds, Brinkman and Peclet numbers on the heat transfer mechanism and rate was analysed for different values of the physical properties ratios (thermal conductivity ratio, heat capacity ratio, viscosity ratio and density ratio).

Effects of Cross-Diffusion on Unsteady Natural Convection past a Vertical Flat Plate in an Electrically Conducting Doubly Stratified Fluid Saturated Brinkman Porous Medium

In this paper, the influence of viscous dissipation and cross-diffusion effects on unsteady natural convective flow of an electrically conducting doubly stratified fluid in a Brinkman porous medium has been analyzed. By using the similarity transformations, the governing differential equations are expressed into a set of non-linear coupled ordinary differential equations along with the suitable boundary conditions. The Crank-Nicolson type scheme developed based on implicit finite difference method has been used to solve the reduced nonlinear boundary value problem. Numerical results for local skin-friction, local Nusselt number, and local Sherwood number profiles are depicted graphically and analyzed in detail for different physical parameters.

Viscous dissipation in 3D spine reconnection solutions

Aims. We consider the influence of viscous dissipation on “spine” reconnection solutions in coronal plasmas. It is known from 2D and 3D “fan” reconnection studies that viscous losses can be important. We extend these arguments to 3D “spine” reconnection solutions. Methods. Steady 3D spine reconnection models were constructed by time relaxation of the governing visco-resistive MHD equations. Scaling laws were derived that compare the relative importance of viscous and resistive damping. Results. It is shown that viscous dissipation in spine reconnection models can dominate resistive damping by many orders of magnitude. A similar conclusion, but with less severe implications, applies to current sheet “fan” solutions. These findings are not sensitive to whether classical or Braginskii viscosity is employed.

Influence of Viscous Dissipation on Mixed Convection in a Non-Darcy Porous Medium Saturated with a Nanofluid

In this study, the effects of viscous dissipation on mixed convection heat and mass transfer along a vertical plate embedded in a nanofluid-saturated non-Darcy porous medium have been investigated. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. The new far-field thermal boundary condition that has been recently developed is employed to properly account for the effect of viscous dissipation in mixed convective transport in a porous medium. The nonlinear governing equations and the associated boundary conditions are transformed to a set of nonsimilar ordinary differential equations and the resulting system of equations is then solved numerically by an improved implicit finite-difference method. The effect of the physical parameters on the flow, heat transfer, and nanoparticle concentration characteristics of the model are presented through graphs and the salient features are discussed. As expected, a significant improvement in the heat transfer coefficient is noticed because of the consideration of the nanofluid in the porous medium. With the increase in the value of the viscous dissipation parameter, a reduction in the non-dimensional heat transfer coefficient is noted while an increase in the nanoparticle mass transfer coefficient is seen. Further, an increase in the mixed convection parameter lowered both the heat and nanoparticle mass transfer rates. Moreover, the increase in the Brownian motion parameter enhanced the nanoparticle mass transfer rate but it reduced the heat transfer rate in the boundary layer. A similar trend is also found with the thermophoresis parameter. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res, 43(5): 397–411, 2014; Published online 3 October 2013 in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21083

Influence of Viscous Dissipation on Free Convection in a Non-Darcy Porous Medium Saturated with Nanofluid in the Presence of Magnetic Field

The effects of viscous dissipation and magnetic field on free convection heat and mass transfer along a vertical plate embedded in a nanofluid saturated non-Darcy porous medium have been studied. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. The nonlinear governing equations and their associated boundary conditions are initially cast into dimensionless form by non-similarity variables. The resulting system of equations is then solved numerically by an accurate implicit finite-difference method. The numerical results are compared and found to be in good agreement with previously published results for a special case of the present investigation. The effect of the physical parameters on the flow, heat transfer and nanoparticle concentration characteristics of the model is presented through graphs and the salient features are discussed.

The influence of viscous dissipation on thermal performance of microchannels with rounded corners

The influence of viscous dissipation on thermal performance of microchannels with rounded corners

Scorch arisen prediction through elastomer flow in extrusion die

The thermal and kinetic behaviour of an elastomer flow inside an extrusion die is numerically investigated. The aim is to control scorch arisen and reduce the heating time in the mould by using viscous dissipation phenomena in order to improve the rubber compound curing efficiency. A three dimensional model, using the particle tracking technique, is developed in order to get thermal, velocity and kinetic fields through the flow. Three common geometries of an elastomer forming process are modeled: a straight runner, a bend zone and a bifurcation. This simulation is applied on the case of an EPDM (ethylene propylene diene monomer) flow. The thermal and rheological properties are experimentally characterized. The influence of viscous dissipation on the reaction progress of the melt is studied on several process conditions. Many criterions relevant for thermal and cure homogeneity are proposed in order to quantify the performance of geometry modifications.