Increase In Radiation Parameter Research Articles

Fe3O4–(CH2OH)2 nanofluid analysis in a porous medium under MHD radiative boundary layer and dusty fluid

In this paper, magnetohydrodynamic (MHD) boundary layer flow and heat transfer of an incompressible Iron (II,III) oxide (Fe3O4)-ethylene glycol ((CH2OH)2) nanoparticle on micropolar fluid with homogeneously suspended dust particles over a stretching sheet in the presence of thermal radiation and Joule heating are investigated. After transforming the partial differential equations (PDEs) governing the problem into the ordinary differential equations (ODEs), Runge–Kutta Fehlberg fourth fifth order numerical method is applied. The main criterion of this paper is to study the effects of different parameters and dimensionless numbers on velocity and temperature distribution in two phases of fluid and dust for two prescribed surface temperature (PST) and prescribed heat flux (PHF) cases. Velocity reduction in both fluid and dust phases is due to the Lorentz force against flow by increasing Hartman number, enhancement of temperature and thickness of thermal boundary layer are due to the increase of radiation parameter and Eckert number for both PST and PHF cases are the most important results. Also, in the final section of this paper, the effect of changes in the value of different parameters on skin friction coefficient and local Nusselt number in (PST and PHF PHF) have been discussed. These results indicated increasing the Hartman parameter (Ha) would cause an increase skin friction coefficient, also increasing the Eckert number would cause an increase local Nusselt number in PST case and reverse effect in PHF case.

Numerical exploration of the combined effects of non-linear thermal radiation and variable thermo-physical properties on the flow of Casson nanofluid over a wedge

PurposeThe effect of non-linear thermal radiation and variable thermo-physical properties are investigated in the Falkner-Skan flow of a Casson nanofluid in the presence of magnetic field. The paper aims to discuss this issue.Design/methodology/approachSelected bunch of similarity transformations are used to reduce the governing partial differential equations into a set of non-linear ordinary differential equations. The resultant equations are numerically solved using Runge-Kutta-Fehlberg fourth-fifth-order method along with shooting technique.FindingsThe velocity, temperature and concentration profiles are evaluated for several emerging physical parameters and are analyzed through graphs and tables in detail.Research limitations/implicationsThis study only begins to reveal the research potential and pitfalls of research and publishing on boundary-layer flow, heat and mass transfer of Casson nanofluid past and the moving and static wedge-shaped bodies.Originality/valueIt is found that the presence of non-linear thermal radiation and variable properties has more influence in heat transfer. Furthermore, temperature profile increases as the radiation parameter increases.

Melting heat and thermal radiation effects in stretched flow of an Oldroyd-B fluid

The incompressible flow of a non-Newtonian fluid with mixed convection along a stretching sheet is analyzed. The heat transfer phenomenon is discussed through thermal radiation. The effects of the melting heat transfer and heat generation/absorption are also taken. Suitable transformations are utilized to attain the nonlinear ordinary differential expressions. The convergent series solutions are presented. The fluid flow, temperature, and surface heat transfer rate are examined graphically. It is observed that the velocity decreases when the relaxation time increases while increases when the retardation time is constant. The results also reveal that the temperature distribution reduces when the radiation parameter increases.

CNT-water nanofluid thermal radiation heat transfer over a stretching sheet considering heat generation

CNT-water nanofluid flow over a stretching plate is examined considering heat generation and thermal radiation effects. Runge–Kutta scheme is utilized to solve the ODEs. Numerical investigation is completed by examining the various values of temperature index parameter, radiation parameter, heat generation parameter and velocity ratio parameter. Results indicated that temperature gradient augments with increase of temperature index parameter and velocity ratio parameter while it reduces with increase of heat generation parameter and radiation parameter.

Combined effect of heat source, porosity and thermal radiation on mixed convection flow in a vertical annulus: An exact solution

This paper examines the effect of heat source, thermal radiation and porosity on mixed convection flow in a vertical annulus filled with porous material. The inner surface of outer cylinder is assumed to be the heated surface. Closed-form expression for temperature, velocity, Nusselt number, skin-friction and mass flow rate are obtained in terms of Bessel’s function and modified Bessel’s function of first and second kind. Based on depicted graphs, fluid temperature and Nusselt number increase with increase in radiation parameter and heat source parameter while velocity as well as skin-friction decreases with increase in radiation parameter and heat source parameter at the surfaces of the cylinder.

Flow and Heat Transfer of Gold-Blood Nanofluid in a Porous Channel with Moving/Stationary Walls

AbstractThe present study investigates the flow and heat transfer characteristics of blood carrying gold nanoparticles in a porous channel with moving/stationary walls in the presence of thermal radiation. Blood is considered as Newtonian fluid which is the base fluid and gold (Au) as nanoparticles. The governing equations are transformed into system of ordinary differential equations by using similarity transformations. The analytical solutions are obtained for the flow variables by employing homotopy analysis method (HAM). The analytical solutions are compared with the numerical solutions which are obtained by shooting technique along with Runge-Kutta scheme. It was noticed that there is a good agreement between analytical and numerical results. The influence of various parameters on velocity, temperature and heat transfer rate of gold-blood nanofluid has been discussed in detail. The temperature of the nanofluid increases with increasing the nanoparticle volume fraction. The heat transfer rate at the top wall increases with increasing nanoparticle volume fraction while it decreases for a given increase in radiation parameter.

Chemical Reaction Effects on an Unsteady MHD Mixed Convective and Radiative Boundary Layer Flow over a Circular Cylinder

A mathematical model is presented for an optically dense fluid past an isothermal circular cylinder with chemical reaction taking place in it. A constant, static, magnetic field is applied transverse to the cylinder surface. The cylinder surface is maintained at a constant temperature. New variables are introduced to transform the complex geometry into a simple shape and the boundary layer conservation equations, which are parabolic in nature, are normalized into non-similar form and then solved numerically with the well-tested, efficient, implicit, Crank-Nicolson finite difference scheme. Numerical computations are made and the effects of the various material parameters on the velocity, temperature and concentration as well as the surface skin friction and surface heat and mass transfer rates are illustrated graphs and tables. Increasing magnetohydrodynamic body force parameter (M) is found to decelerate the flow but enhance temperatures. Thermal radiation is seen to reduce both velocity and temperature in the boundary layer. Local Nusselt number is also found to be enhanced with increasing radiation parameter.

Unsteady MHD Mixed Convection Slip Flow of Casson Fluid over Nonlinearly Stretching Sheet Embedded in a Porous Medium with Chemical Reaction, Thermal Radiation, Heat Generation/Absorption and Convective Boundary Conditions.

Numerical results are presented for the effect of first order chemical reaction and thermal radiation on mixed convection flow of Casson fluid in the presence of magnetic field. The flow is generated due to unsteady nonlinearly stretching sheet placed inside a porous medium. Convective conditions on wall temperature and wall concentration are also employed in the investigation. The governing partial differential equations are converted to ordinary differential equations using suitable transformations and then solved numerically via Keller-box method. It is noticed that fluid velocity rises with increase in radiation parameter in the case of assisting flow and is opposite in the case of opposing fluid while radiation parameter has no effect on fluid velocity in the forced convection. It is also seen that fluid velocity and concentration enhances in the case of generative chemical reaction whereas both profiles reduces in the case of destructive chemical reaction. Further, increase in local unsteadiness parameter reduces fluid velocity, temperature and concentration. Over all the effects of physical parameters on fluid velocity, temperature and concentration distribution as well as on the wall shear stress, heat and mass transfer rates are discussed in detail.

Combined Effects of Nonlinear Thermal Radiation and Internal Heat Generation/Absorption on Heat and Mass Transfer in a Thin Liquid Film on a Permeable Unsteady Stretching Surface with Convective Boundary Condition

An analysis has been carried out to study the combined effects of nonlinear thermal radiation and internal heat source/sink on heat and mass transfer in a thin liquid film over a permeable unsteady stretching sheet with suction/injection in the presence of chemical reaction. Since the momentum, energy and mass diffusion equations are highly non-linear, the problem is solved numerically. The governing equations are first reduced to a set of ordinary differential equations by using the similarity transformations and then the resulting nonlinear ordinary differential equations are solved using Runge–Kutta–Fehlberg method with shooting technique. The effects of various physical parameters on heat and mass transfer in a thin liquid film are presented graphically and in tabular forms. Numerical results are compared with the published results for some limiting cases. It is found that increase in the unsteadiness parameter leads to increase in the velocity distribution, temperature gradient and concentration gradient due to reduction in the thin film thickness. Also, increase in the thermal radiation parameter decreases the temperature gradient whereas reverse effect is seen on the concentration gradient by increasing the values of the Schmidt number.

Effects of Variable Thermal Conductivity with Thermal Radiation on MHD Flow and Heat Transfer of Casson Liquid Film Over an Unsteady Stretching Surface

In the present work, the hydromagnetic boundary layer flow and heat transfer of Casson fluid in a thin liquid film over an unsteady stretching sheet in the presence of variable thermal conductivity, thermal radiation, and viscous dissipation is investigated numerically. The Casson fluid model is applied to characterize the non-Newtonian fluid behavior. Similarity equations are derived and then solved numerically by using a shooting method with fourth order Runge–Kutta integration scheme. Comparisons with previous literature are accomplished and obtained an excellent agreement. The influences of parameters governing a thin liquid film of Casson fluid and heat transfer characteristics are presented graphically and analyzed. It is observed that the heat transfer rate diminishes with a rise in thermal conductivity parameter and Eckert number. Further, the opposite influence is found with an increase in radiation parameter.

Free Convection Heat and Mass Transfer Flow for Magnetohydrodynamic Chemically Reacting and Radiating Elastico-Viscous Fluid Past a Vertical Permeable Plate with Gravity Modulation

An analysis of a two-dimensional unsteady magnetohydrodynamic free convective heat and mass transfer flow of an electrically conducting, optically thin, incompressible, and radiating elastico-viscous fluid (characterised by Walters’ liquid $${B}'$$ ) past a vertical permeable infinite plate embedded in a uniform porous medium with gravity modulation is considered. It is assumed that there exists a homogeneous first-order chemical reaction. Analytical solutions for velocity, temperature and concentration field have been derived. The effects of gravity modulation, radiation, and chemical reaction on velocity profile and shear stress for both Newtonian and elastico-viscous fluid have been studied and presented graphically. It was observed that velocity distribution increases with an increase in gravity modulation parameter and radiation parameter for both Newtonian and elastico-viscous fluid, where as it shows reverse effects in the case of magnetic field parameter and viscoelastic parameter. It is seen that viscous drag on the plate is reduced under the effect of chemical reaction parameter, where as it shows reverse effect in the case of gravity modulation parameter and radiation parameter.

Flow and heat transfer of MHD nanofluid between parallel plates in the presence of thermal radiation

In this paper, the unsteady squeezing flow and heat transfer of MHD nanofluid between the infinite parallel plates with thermal radiation effect is investigated. A similarity transformation is used to convert the governing momentum and energy equations into non-linear ordinary differential equations with the appropriate boundary conditions. These non-linear ordinary differential equations are solved analytically by Duan–Rach Approach (DRA). This method allows us to find a solution without using numerical methods to evaluate the undetermined coefficients. This method modifies the standard Adomian Decomposition Method (ADM) by evaluating the inverse operators at the boundary conditions directly. The effects of various parameters such as the squeeze number, the magnetic parameter, the volume fraction of nanofluid, the Eckert number and the radiation parameter are investigated on the velocity and temperature. Also, the values of skin friction coefficient and the Nusselt number are calculated and presented through figures. The results show that the temperature profile and Nusselt number increase with the increase of radiation parameter. Furthermore, the limiting cases are obtained and are found to be in good agreement with the previously published results.

MHD natural convection flow of viscoelastic fluid over an accelerating permeable surface with thermal radiation and heat source or sink: Spectral Homotopy Analysis Approach

Abstract An analysis is presented to study the effects of viscous dissipation and viscoelastic parameter on MHD natural convection flow of viscoelastic fluid over an accelerating permeable surface with thermal radiation and heat source/sink. The governing differential equations that are highly nonlinear are transformed by similarity variables and solved using Spectral Homotopy Analysis Method (SHAM). The effects of various pertinent parameters on the velocity and temperature profiles as well as the skin friction coefficient and the local Nusselt number are presented graphically and in tabular form. The SHAM results are compared favorably with already established results in literatures. It is found that the magnetic field acts as a retarding force on the velocity profile of the flow but has a propelling effect on the thermal condition of the flow. It was revealed that an increase in thermal radiation parameter of the flow produces significant increase in the thermal condition of the fluid temperature.

Natural convection on heat transfer flow of non-newtonian second grade fluid over horizontal circular cylinder with thermal radiation

This article numerically studies for multi-physical transport of an optically-dense, free convective incompressible non-Newtonian second grade fluid past an isothermal, impermeable horizontal circular cylinder. The governing boundary layer equations for momentum and energy transport, which are parabolic in nature, have been reduced to non-similarity non-linear conservation equations using appropriate transformations and then solved numerically by employing with most validated, efficient implicit finite difference method with Keller box scheme. The numerical code is validated with previously existing results and found to be very good agreement. The results are reported graphically and in tabular form for various physical parameters; Deborah number, Prandtl number and thermal radiation on flow velocity and temperature profiles. Furthermore, the effects of these parameters on non dimensional wall shear stress (skin friction) and surface heat transfer rate (Nusselt number) are also investigated. Increasing the Deborah number reduces velocity profile, skin friction and Nusselt number where as it enhances the temperature profile. Increasing Prandtl number decelerates the flow velocity, temperature and skin friction but Nusselt number enhances considerably. Increase in radiation parameter retards the flow velocity, temperature profiles and skin friction. But Nusselt number enhances markedly with increase in radiation parameter. Applications of the model arise in polymer processing in chemical engineering, metallurgical material processing.

Analysis of Heat Transfer on MHD Peristaltic Blood Flow with Porous Medium through Coaxial Vertical Tapered Asymmetric Channel with Radiation – Blood Flow Study

We study the analysis of heat transfer on MHD peristaltic flow with porous medium through coaxial tapered asymmetric channel with radiation effect under the assumptions of long wavelength approximation with low Reynolds number. The expressions of the axial velocity, pressure gradient, volume flow rate, average volume flow rate, pressure rise, temperature and hear transfer coefficient at y = h1and y = h2 are all obtained and the temperature and hear transfer coefficient at y = h1and y = h2 are discussed through the graphs. It is noted that the temperature increases with increase in radiation parameter and Prandtl number, heat generation parameter, non-uniform parameter and phase angle φ.

Effects of thermal radiation, Soret and Dufour on an unsteady heat and mass transfer flow of a chemically reacting fluid past a semi-infinite vertical plate with viscous dissipation

In this paper, the influence of some thermo-physical properties of fluid on heat and mass transfer flow past semi-infinite moving vertical plate is considered. The fluid considered is optically thin such that the thermal radiative heat loss on the fluid is modeled using Rosseland approximation. The governing equations representing the physical model is a system of partial differential equations which are transformed into systems of coupled non-linear partial differential equation by introducing non-dimensional variables. The resulting equations are solved using the spectral relaxation method (SRM). The result shows that an increase in Eckert number of the fluid actually increases the velocity and temperature profiles of the flow. Whereas an increase in thermal radiation parameter reduces the temperature distribution when the plate is being cooled. The computational results for velocity, temperature and the concentration profiles are displayed graphically for various flow pertinent parameters.

Exact analysis for the effect of heat transfer on MHD and radiation Marangoni boundary layer nanofluid flow past a surface embedded in a porous medium

In the presence of a magnetic field, thermal radiation and with suction/injection, Marangoni boundary layer flow past a surface embedded in a porous medium saturated by a water based nanofluid containing two different types of nanoparticles, namely Copper and Titanium dioxide, has been studied. Exact solutions of the resulted equations were solved using a new approach via Laplace transform. Influence of the velocity profile and temperature distribution for the present nanofluids was investigated under effect of the involved parameters.It was found that the velocities of the two investigated nanoparticles decrease significantly with an increase in the solid volume fraction. In addition, the effective electrical conductivity parameter is mandatory and should be taken into account on applying the magnetic field; otherwise a spurious physical sight is to be gained. As expected, the magnetic parameter decelerates the fluid velocity and increases its temperature, as well, for all nanoparticles considered and for all investigated cases of the suction/injection parameter, the temperature profiles increase as radiation parameter increases. Further, the fluid suction decreases the fluid velocity and, therefore, thickness of the hydrodynamic boundary layer, regarding, the fluid temperature and thermal boundary layer decreases as well. However, fluid injection produces the opposite effect.

Wire Coating Analysis in MHD Flow and Heat Transfer of a Radiative Third Grade Fluid with Variable Viscosity in a Porous Medium

Wire coating process is a continuous extrusion process for primary insulation of conducting wires with molten polymers for mechanical strength and protection in aggressive environments. In the present study wire coating is performed using radiative melt polymer satisfying third grade fluid model. The novelty of this study is to analyze the effect of porosity, thermal radiation parameter and varying temperature dependent viscosity on the wire coating. Reynolds Model and Vogel’s Model have been considered to account for temperature dependent viscosity. The equations characterizing the flow and heat transfer phenomena are solved numerically by fourth order Runge-Kutta method and the effects of pertinent parameters are shown with the help of graphs. It is interesting to remark that an increase in non-Newtonian parameter increases the velocity in the absence of porous matrix which coincides with the results reported earlier but in the presence of porous matrix the velocity decreases in the entire span of the flow domain. It is also interesting to note that increase in thermal radiation parameter accelerates the process in the presence of porous matrix. Further, the flow instability in the flows of extrusion die is well marked in case of Vogel’s model as pointed out by Nhan-Phan-Thien.

Effects of Time Dependent Variable Temperature and Concentration Boundary Layer on MHD Free Convection Flow Past a Vertical Porous Plate in the Presence of Thermal Radiation and Chemical Reaction

An analytical solution is presented for the case of time dependent variable temperature and variable concentration boundary layer on unsteady MHD free convection flow past a vertical porous plate in the presence of thermal radiation, thermal diffusion and first order chemical reaction. The dimension less governing equations are solved analytically and the expressions for temperature, concentration and velocity fields are determined using the Laplace transform technique. Finally, the influence of various physical parameters on the temperature, concentration and velocity fields is graphically studied and discussed. The expressions for local skin friction, Nusselt number and Sherwood number are derived and discussed with the help of tables. It noticed that Skin friction increase with an increase in magnetic parameter, Prandtl number, radiation parameter and chemical reaction parameter while it decrease with an increase in Grashof number, modified Grashof number, permeability parameter, heat source and Schmidt number. The rate of heat transfer increase with increasing values of Prandtl number and radiation parameter while it decreases with increasing value of heat source. The rate of mass transfer increases with increasing values of Schmidt number and chemical reaction parameter.

Reynold's model viscosity on radiative MHD flow in a porous medium between two vertical wavy walls

The two dimensional heat transfer of a free convective–radiative MHD (magnetohydrodynamics) flows with variable viscosity and heat source of a viscous incompressible fluid in a porous medium between two vertical wavy walls was investigated. The fluid viscosity is assumed to vary as an exponential function of temperature. The flow is assumed to consist of a mean part and a perturbed part. The perturbed quantities were expressed in terms of complex exponential series of plane wave equation. The resultant differential equations governing the flow were non-dimensionalised and solved using Differential Transform Method (DTM). The numerical computations were presented in tabular and graphical forms for various fluid parameters. It shows that an increase in radiation, variable viscosity and permeability parameters cause a rise in velocity profile. Nusselt number increases with increase in heat source and decreases with increase in radiation parameter at both walls.