Combined Effects Of Thermal Radiation Research Articles

Hydromagnetic flow of micropolar nanofluids with co-effects of thermal radiation and chemical reaction over an inclined permeable stretching surface

BackgroundMany investigations have been conducted by researchers across the globe to examine the behavior of fluids with respect to the influence of some constituent parameters and novel results have been obtained. However, the combined effect of thermal radiation and chemical reaction on micropolar nanofluid flow over an inclined stretching surface has not been well elucidated. This article, therefore, employed the mathematical model of Buongiorno for hydromagnetic micropolar nanofluids to study the effect of thermal radiation and chemical reaction on such fluids. The model examined the influence of thermophoresis, Brownian motion and the angle of inclination to the stretching surface on the fluid flow. The set of governing equations were transformed into ordinary differential equations using some similarity transformations and then numerically simplified through Chebyshev collocation method on MATHEMATICA software.ResultsThe graphs thus derived were used to interpret the effect of some physical parameters on the fluid flow. It was observed among other results obtained, that thermal radiation, Brownian motion and thermophoresis enhanced the temperature profile of the flow while the inclination angle and chemical reaction declined the velocity and concentration, respectively.ConclusionsThese parameters tested on the various profiles proved observably effective on micropolar nanofluids and should be considered whenever improvement or decrease in the profiles are needed.

EFFECTS OF THERMAL RADIATION AND BUOYANCY FORCE ON TRANSIENT HARTMANN FLOW IN A CHANNEL WITH PERMEABLE WALLS

The combined effects of thermal radiation, buoyancy force and variable heat source on an unsteady MHD flow of a conducting fluid through a porous walled channel is theoretically investigated. Base on some simplified assumptions, the model partial differential equations are obtained and tackled analytically using variable separable technique. Numerical solutions depicting the impact of various embedded thermophysical parameters on the fluid velocity and temperature profiles, skin friction and Nusselt number are displayed graphically and quantitatively discussed. An escalation in both skin friction and heat transfer rate is observed with a rise in fluid injection–suction at the channel walls.

Combined effects of thermal radiation and thermophoretic motion on mixed convection boundary layer flow

The current study is concerned with the investigation of the combined effects of thermophoretic motion and thermal radiation on steady, viscous, incompressible and two-dimensional mixed convection flow of optically dense grey fluid. The governing equations are made dimensionless by using suitable dimensionless variables and further are transformed into a convenient form for a numerical algorithm. The transformed flow model is integrated by using an efficient finite difference methd. Effects of the assorted parameters involved in the flow model such as Prandtl number, mixed convection parameter, modified mixed convection parameter, Schmidt number, radiation parameter, thermophoresis parameter and thermophoretic coefficient on velocity field, temperature distribution, and mass concentration are demonstrated graphically. The numerical results of skin friction, the heat transfer rate and the mass transfer rate under the effect of pertinent parameters are displayed in tabular form.

Intrinsic irreversibility of Al2O3–H2O nanofluid Poiseuille flow with variable viscosity and convective cooling

PurposeThis study aims to investigate the flow behavior of aluminum oxide–water nanofluid with variable viscosity flowing through the microchannel parallel with the ground, with low aspect ratio. The study focuses on the first and second law analyses of Poiseuille flow using water as the base fluid with alumina nanoparticles suspended in it. Combined effects of thermal radiation, viscous dissipation, variable viscosity, nanoparticle shape factor and volume fraction on the thermal performance are studied and the in-built irreversibility in the process is examined.Design/methodology/approachThe governing equations with dimensions are reduced to non-dimensional equations by using dimensionless quantities. Then, the Runge–Kutta–Fehlberg shooting scheme tackles the present non-linear equations.FindingsThe outcomes of the present analysis reveal that the activation energy parameter with its increase, depletes the exergetic effectiveness of the system, thus defending the fact to keep the activation energy parameter the lowest as possible for the system efficiency. In addition, thermal radiation and Biot number enhance the release of heat energy, thereby cooling the system. Bejan number graph exhibits the decreasing behavior for the increased nanoparticle shape factor, whereas the temperature enhances with the rise in nanoparticle shape factor.Originality/valueThe effects of nanoparticle shape factor in Poiseuille flow for alumina–water nanoliquid in low aspect ratio microchannel is inspected at the earliest. Exergetic effectiveness of the system is studied and heat transfer characteristics are explored for thermal radiation effect and activation energy parameter. Besides, .

Characteristics of combined heat and mass transfer on mixed convection flow of Sisko fluid model: A numerical study

In this paper, the combined heat and mass transfer of mixed convection, non-similar Sisko fluid flow in the presence of a magnetic field is studied. The combined effects of thermal radiation and heat generation/absorption are examined for Sisko fluid flow via local non-similar method. For the radiative heat transfer, Rosseland approximation model is used. The governing partial differential equations of the present problem are transformed into a system of nonlinear ordinary differential equations by employing the Sparrow–Quack–Boerner local non-similarity method (LNM). The obtained equations are then numerically investigated by utilizing the bvp4c function in MATLAB. The impact of different supervising parameters on the velocity, temperature, skin friction and rate of heat transfer is performed graphically. It is observed that the velocity is more for a higher rate of the buoyancy force parameter while it is less for opposing buoyancy fluid. The thermal boundary layer thickness for the shear thickening fluids is smaller than the shear thinning fluids.

Analysis of activation energy in quadratic convective flow of a micropolar fluid with chemical reaction and suction/injection effects

PurposeThe purpose of this paper is to analyze the combined effects of thermal radiation and activation energy with a chemical reaction on the quadratic convective flow of a micropolar fluid over an inclined plate. Convective thermal boundary condition and suction/injection effects are considered at the surface of an inclined plate.Design/methodology/approachThe convection along with nonlinear Boussinesq approximation (i.e. quadratic convection or nonlinear convection) and usual boundary layer assumptions is employed in the mathematical formulation. Highly coupled nonlinear governing equations are tackled by a combined local non-similarity and successive linearization techniques.FindingsThe behavior of various pertinent parameters on the fluid flow characteristics is conferred through graphs and it reveals that the qualitative behaviors of velocity, temperature, skin friction and heat transfer rates of a micropolar fluid are similar for Biot number and radiation parameters. The suction/injection and activation energy parameters increase the concentration of the micropolar fluid within the boundary layer, while the chemical reaction parameter reduces the concentration in the same region. Further, this quadratic convection shows a strong influence on the fluid flow characteristics and then the impact of pertinent parameters is more prominent on the physical quantities, compared therewith results of the linear convection.Practical implicationsThis kind of investigation is useful in the mechanism of combustion, aerosol technology, high-temperature polymeric mixtures and solar collectors which are operated at moderate to very high temperatures.Originality/valueThis attempt is a unique contribution to the establishment of both micropolar fluid and activation energy. This kind of study even in the absence of quadratic convection is not yet noted.

The effects of radiation and chemical reaction on MHD mixed convective flow and mass transfer from a vertical surface with Ohmic heating and viscous dissipation

PurposeThe purpose of this paper is to address the combined effects of thermal radiation and chemical reaction on steady MHD mixed convective heat and mass transfer flow past a vertical surface under the influence of Joule and viscous dissipation.Design/methodology/approachThe governing system of partial differential equations is transformed to dimensionless equations using dimensionless variables. The dimensionless equations are then solved analytically using perturbation technique.FindingsWith the help of graphs, the effects of the various important parameters entering into the problem on the dimensionless velocity, dimensionless temperature and dimensionless concentration fields within the boundary layer are discussed. The authors noticed that the velocity increases with an increase in the porosity parameter. An increase in the Prandtl number Pr, decreases the velocity and the temperature field. An increase in the radiation parameter, decreases the velocity and the temperature field. Also the effects of the pertinent parameters on the skin-friction coefficient and rates of heat and mass transfer in terms of the Nusselt and Sherwood numbers are presented numerically in tabular form.Originality/valueTo the best of the authors’ knowledge, recent this work has not been finished by any other researchers.

Magnetohydrodynamic flow of molybdenum disulfide nanofluid in a channel with shape effects

PurposeThe purpose of this paper is to examine the combined effects of thermal radiation and magnetic field of molybdenum disulfide nanofluid in a channel with changing walls. Water is considered as a Newtonian fluid and treated as a base fluid and MoS2 as nanoparticles with different shapes (spherical, cylindrical and laminar). The main structures of partial differential equations are taken in the form of continuity, momentum and energy equations.Design/methodology/approachThe governing partial differential equations are converted into a set of nonlinear ordinary differential equations by applying a suitable similarity transformation and then solved numerically via a three-stage Lobatto III-A formula.FindingsAll obtained unknown functions are discussed in detail after plotting the numerical results against different arising physical parameters. The validations of numerical results have been taken into account with other works reported in literature and are found to be in an excellent agreement. The study reveals that the Nusselt number increases by increasing the solid volume fraction for different shapes of nanoparticles, and an increase in the values of wall expansion ratio α increases the velocity profile f′(η) from lower wall to the center of the channel and decreases afterwards.Originality/valueIn this paper, a numerical method was utilized to investigate the influence of molybdenum disulfide (MoS2) nanoparticles shapes on MHD flow of nanofluid in a channel. The validity of the literature review cited above ensures that the current study has never been reported before and it is quite new; therefore, in case of validity of the results, a three-stage Lobattoo III-A formula is implemented in Matlab 15 by built in routine “bvp4c,” and it is found to be in an excellent agreement with the literature published before.

Numerical investigation of entropy generation in microporous channel with thermal radiation and buoyancy force

Microporous channels found to have extensive applications in many fields of engineering, particularly in thermal and petrochemical engineering. In particular, the microelectromechanical systems are useful to develop a large number of microscopic devices and systems such as micromixture, microheat exchangers, microchannel heat sinks, microfuel cells. The present work aims to scrutinize the combined effects of thermal radiation and buoyancy force on entropy generation in magneto-hydrodynamic Jeffrey fluid flow through a vertical microporous channel. The model equations of linear momentum and energy balance are developed and tackled numerically using fourth-order Runge–Kutta method. The results are exhibited pictorially and discussed quantitatively for active parameters which emerged in the mathematical formulation. Validation with previously published work is included, and the current results are in good agreement. It is found that the effects of viscous dissipation and suction/injection on entropy generation in microchannel are important and should not be ignored. Further, it is noticed that the fluid temperature retards with an increasing value of suction and the effect is reversed in the case of injection.

Thermal radiation and slip effects on magnetohydrodynamic (MHD) stagnation point flow of Casson fluid over a convective stretching sheet

Current study examines the combined effect of thermal radiation and velocity slip along a convective heated stretching sheet. magnetohydrodynamic (MHD) effect near the stagnation point is also under consideration. The main structure of partial differential equations attained in the form of momentum, energy and concentration equations. For a self-similar solution, the system of governing PDEs assimilated into the set of nonlinear ordinary differential equations by applying suitable similarity transformation. Resulting nonlinear ODEs are successfully solved via Runge-Kutta-Fehlberg method. All obtained unknown functions are discussed in detail after plotting the numerical results against different arising physical parameters. The validations of numerical results have been taken into account with two different numerical approaches and it is found to be in excellent agreement with the numerical results. The study reveals that concentration boundary layer thickness decreases by increasing the values of Schmidt number and increases by increasing the chemical reaction parameter.

Unsteady MHD free convective chemically reacting fluid flow over a vertical plate with thermal radiation, Dufour, Soret and constant suction effects

Unsteady MHD free convective flow of a chemically reacting incompressible fluid over a vertical porous plate under the combined effects of thermal radiation, Dufour, Soret and constant suction is examined. The governing non-linear equations are solved semi analytically using the methods of similarity transformation and perturbation series expansions. Expressions for the velocity, temperature, concentration and Nusselt number for the flow are obtained and presented graphically. The analysis shows that Dufour number increases the temperature and velocity; Soret number increases the concentration and velocity; suction parameter decreases the temperature, concentration and velocity, but increases the Nusselt number; chemical reaction rate decreases the temperature but increases the concentration, velocity and Nusselt number; magnetic field force increases the velocity; Grashof numbers increase the velocity when their values are increasingly varied.

Numerical Analysis of the Unsteady Natural Convection MHD Couette Nanofluid Flow in the Presence of Thermal Radiation Using Single and Two-Phase Nanofluid Models for Cu–Water Nanofluids

The unsteady Couette nanofluid flow with heat transfer is investigated numerically for copper–water nanofluids under the combined effects of thermal radiation and a uniform transverse magnetic field with variable thermo-physical properties, in the case where the flow is established vertically between two parallel plates, so that one of them has an accelerated motion. The homogeneous single-phase model (i.e., Tiwari and Das’s nanofluid model) and the two-phase mixture model (i.e., Buongiorno’s nanofluid model) are utilized in this study together with Corcione’s model to further investigate and clarify the differences between those models and evaluate the validity of the single-phase model for studying the unsteady natural convection MHD Couette nanofluid flow with thermal radiation. In this investigation, we assume that the studied nanofluid is electrically conducting and has a Newtonian rheological behavior. The nonlinear dynamical system of partial differential equations are solved numerically by means of the Gear–Chebyshev–Gauss–Lobatto collocation technique for zero nanoparticles mass flux and no-slip impermeable conditions at the isothermal vertical plates. In a special case, the present numerical solution is also validated analytically and numerically with the earlier available results. For both nanofluid models, the effects of major parameters on the dimensionless velocity, temperature and volumetric fraction of nanoparticles are analysed via representative profiles, whereas the skin friction factor and the heat transfer rate are estimated numerically and discussed through tabular illustrations.

Numerical investigation of magnetic nanofluids flow over rotating disk embedded in a porous medium

Combined effects of thermal radiation and variable viscosity on a time-dependent boundary-layer flow of magnetic nanofluids over a rotating disk in the presence of the porous medium have been numerically investigated. To carry out the study, hydrocarbon based magnetic nanofluid containing magnetite Fe3O4 particles of 10 nm with magnetic phase concentration of 10% has been taken. For numerical solutions of the modelled system containing the governing equation of the flow, a MATLAB tool ODE45 is employed with shooting technique for the initial guess of the unknown boundary conditions. The flow phenomenon and heat transfer on the plate surface are characterised by various flow parameters such as viscosity variations, unsteady rotation parameter, Prandtl number, and radiation parameter. Also, a comparative thermal analysis has been carried out for magnetic nanofluids having three different bases viz. hydrocarbon, fluorocarbon, and water. Results reveal that heat transfer rate of hydrocarbon base magnetic nanofluids is 73.4511% faster than water base magnetic nanofluids, and 239.7458% faster than fluorocarbon base magnetic nanofluids. This enhanced heat transfer capacity of hydrocarbon base magnetic nanofluids will help in improving the performance of oil and ore extraction drilling systems used in mining industry and other geothermal applications.

Phenomenon of Radiation and Viscous Dissipation on Casson Nanoliquid Flow Past a Moving Melting Surface

A combined effect of thermal radiation and viscous dissipation over a melting moving surface is investigated. Casson liquid model is accounted as working liquid. The Brownian motion and thermophoresis in Buogiorno’s type nanofluid are retained. Numerical solutions are obtained for the reduced ordinary differential equations via RKF 45 method. The pertinent parameters on velocity, temperature and concentration are analyzed through plots and tables. Output demonstrated that higher values of melting, thermal radiation and viscous dissipation are enhanced the temperature. Validation of the present work is made with the existing literature.

Effects of thermal radiation, viscous and Joule heating on electrical MHD nanofluid with double stratification

The investigation is made to study the combined effects of thermal radiation, viscous dissipation and Joule heating in steady two-dimensional electrical magnetohydrodynamic boundary layer flow of nanofluids using Buongiorno's model over a permeable linear stretching sheet. The system of transport equation incorporate the effects of Brownian motion, thermophoresis, thermal and concentration stratifications in the presence of nano energy conversion emerging parameters. A similarity transformation is implemented to reduce the boundary layer flow equations to a system of nonlinear ordinary differential equations, then solved by implicit finite difference scheme. The computation has been investigated for certain range of values required emerging parameters M(0 ≤ M ≤ 2.5), E1(0 ≤ E1 ≤ 1.0), s(−0.4≤s≤1.0), λ(0.1 ≤ λ ≤ 2.0), N(0.1 ≤ N ≤ 1.0), Rd(0 ≤ Rd ≤ 1.0), Nb(0.1 ≤ Nb ≤ 0.5), Nt(0.1 ≤ Nt ≤ 0.5), Ec(0 ≤ Ec ≤ 0.8), st(0 ≤ st ≤ 0.7), Le(2 ≤ Le ≤ 10), sc(0 ≤ sc ≤ 0.7). Velocity field enhances with the electric field and mixed convection but decreases with fluid suction. Electric field resolved the sticking effects due to the magnetic field. Thermal and concentration stratifications lead to a reduction in temperature and nanoparticle concentration. Heat conduction is sensitive to an increase in an electric field, thermal radiation and viscous dissipation. The rate of heat and mass transfer reduces by increasing thermophoresis and thermal stratifications and it increases for larger values of suction. Numerical values are obtained for the skin friction, local Nusselt and Sherwood number for different involving parameters tabulated and examined. We compare the present numerical solution in limiting sense with previously published investigation presented and examined reveals good agreement.

Nanoparticle shapes on electric and magnetic force in water, ethylene glycol and engine oil based Cu, Al2O3 and SWCNTs

Contribute of nanoparticle shapes on MHD nanofluid flow of water, ethylene glycol and engine oil based Cu, Al2O3 and SWCNTs over a stretched surface in the presence of thermal radiation has been investigated. The three classic models of nanoparticle shapes are registered into report, i.e. sphere (m=3.0), cylinder (m=6.3698) and lamina (m=16.1576). The controlling partial differential equations (PDEs) are regenerated into ordinary differential equations (ODEs) by manipulating irrefutable accordance conversion and it is proposed numerically by executing Runge Kutta Fehlberg method with shooting technique. It is recognized that the lamina shape (m=16.1576) SWCNTs in the SWCNTs-engine oil shows a powerful impact on temperature distribution with increase of nanoparticle volume fraction. Nanoparticle shapes have an enlightened outcome on particle transport and heat transfer. The shape of the nanoparticles, particularly the lamina SWCNTs – engine oil with combined effect of thermal radiation in the presence of magnetic field is encountered an important role on cosmical, geophysical fluid dynamics; also in solar physics, involved in the sunspot development, solar cycle and medicine research.

Influence of Brownian Motion and Thermal Radiation on Heat Transfer of a Nanofluid Over Stretching Sheet with Slip Velocity

In this study combined effect of thermal radiation and velocity slip in the boundary layer flow and heat transfer over a stretching surface with Brownian motion is considered. The similarity transformation and Runge–Kutta–Fehlberg method with shooting technique is used to solved the set of nonlinear ordinary differential equations. The influence of important physical parameters such as Prandtl number, slip factor, Brownian motion, Lewis number and thermophoretic parameters are analyzed on the velocity, temperature, surface shear stress, Nusselt number and Sherwood number. The results show that the effect of increase in the internal heat source/sink parameter increases the temperature in the thermal boundary layer. Further, local Nusselt number decreases with an increase in the value of the thermophoretic parameter, Brownian motion parameter and internal heat source/sink parameter. Also, it can be concluded that the effect of slip velocity is to decrease the shear stress at the surface of the stretching sheet.

Entropy Generation with nonlinear heat and Mass transfer on MHD Boundary Layer over a Moving Surface using SLM

AbstractIn this article, entropy generation with combined effects of thermal radiation and chemical reaction on MHD boundary layer over a moving surface has been investigated. The governing flow comprises of linear momentum equation, energy, and concentration equations which are modified with the help of similarity variables. The reduced resulting nonlinear coupled ordinary differential equations are solved with the help of Successive linearization method (SLM) and Chebyshev spectral collocation method. The impact of all the physical parameters is demonstrated numerically and graphically. A detailed analysis have been given for all the pertinent parameters such as Hartmann number, porosity parameter, Prandtl number, radiation parameter, suction/injection parameter, moving parameter, Brinkmann number, Reynolds number, chemical reaction parameter and Schmidt number on velocity, temperature, concentration and entropy profile as well as the Skin friction coefficient, Nusselt number and Sherwood number are also conducted. The numerical comparison has also been given to the existing published literature.

On combined effect of thermal radiation and viscous dissipation in hydromagnetic micropolar fluid flow between two stretchable disks

In this paper, we investigate numerically the flow and heat transfer characteristics of a viscous incompressible electrically conducting micropolar fluid between two infinite uniformly stretching disks, taking the radiation and viscous dissipation effects into consideration. The transformed self similar coupled ordinary differential equations are solved using quasi-linearization method. The study may be beneficial in flow and thermal control of polymeric processing.

Thermal Radiation Effect on the MHD Turbulent Compressible Boundary Layer Flow with Adverse Pressure Gradient, Heat Transfer and Local Suction

The combined effect of magnetic field, thermal radiation and local suction on the steady turbulent compressible boundary layer flow with adverse pressure gradient is numerically studied. The magnetic field is constant and applied transversely to the direction of the flow. The fluid is subjected to a localized suction and is considered as a radiative optically thin gray fluid. The Reynolds Averaged Boundary Layer (RABL) equations with appropriate boundary conditions are transformed using the compressible Falkner Skan transformation. The nonlinear and coupled system of partial differential equations (PDEs) is solved using the Keller box method. For the eddy-kinematic viscosity the Baldwin Lomax turbulent model and for the turbulent Prandtl number the extended Kays Crawford model are used. The numerical results show that the flow field can be controlled by the combined effect of the applied magnetic field, thermal radiation, and localized suction, moving the separation point, xs , downstream towards the plate’s end, and increasing total drag, D . The combined effect of thermal radiation and magnetic field has a cooling effect on the fluid at the wall vicinity. The combined effect has a greater influence in the case of high free-stream temperature.