Influence Of Thermal Radiation Research Articles

Numerical simulation of thermal radiation influence on natural convection in a trapezoidal enclosure: Heat flow visualization through energy flux vectors

A theoretical and numerical study of natural convection in two-dimensional laminar incompressible flow in a trapezoidal enclosurein the presence of thermal radiation is conducted, motivated by energy systems applications. Heat flow visualization via the method of energy flux vectors (EFVs) is also included. The trapezoidal cavity has an inclined top wall which in addition to the bottom wall is maintained at constant temperature, whereas the remaining (vertical side) walls are adiabatic. The governing partial differential conservation equations are transformed using a vorticity-stream function formulation and non-dimensional variables and the resulting nonlinear boundary value problem is solved using a finite difference method with incremental time steps. EFVs provide abundant details of the heat flow at the core of the enclosure. The larger energy flux vectors indicate high temperature gradient zones and the sparse EFVs correspond to low temperature gradient zone. Heat flow distribution in the trapezoidal enclosure can be clearly elaborated via energy flux vectors and provides a deeper insight into thermal characteristics. A comprehensive parametric study is performed to evaluate the impact of Rayleigh number (buoyancy parameter) and radiation parameter on transport phenomena. The computations indicate that local Nusselt number and velocity are increasing functions of the Rayleigh number and radiation parameter. Significant changes in streamlines, temperature contours and energy streamlines for high Rayleigh number are observed. The energy flux vectors show that a large eddy is formed within the enclosure which migrates towards the cold wall. Greater thermal buoyancy force accelerates the primary flow whereas it decelerates the secondary flow. The simulations are relevant to solar collector systems, enclosure fire dynamics, electronic cooling and fuel cell systems. Furthermore, the computations furnish a good benchmark for more general computational fluid dynamics (CFD) analysis with commercial software e.g. ANSYS FLUENT.

Numerical computation on Marangoni convective flow of two‐phase MHD dusty nanofluids under Brownian motion and thermophoresis effects

AbstractThe current theoretical study describes the Marangoni thermal convective flow of magnetohydrodynamic dusty nanofluids along a wavy vertical surface. The two‐phase mathematical model is developed under the influence of thermal radiation and exponentially varying space‐dependent heat source. Pure and hybrid nanoparticles together with dust particle suspension in the base fluid are taken into consideration to characterize the behavior of the flow. Brownian motion and thermophoresis mechanisms are considered, since it enhances the convection features of dusty nanofluid. Appropriate transformations are adopted to modify the flow governing equations and boundary conditions to dimensionless form. The forward finite difference scheme is implemented to illustrate the resultant coupled partial differential equations. The Newton quasi‐linearization technique is utilized to reduce the nonlinear system into a linear form, which is solved thereafter by Thomas algorithm. The responses of velocity, temperature, concentration, friction factor, and heat and mass transfer rate profiles with various governing parameters are discussed and portrayed graphically. The study evidences that the radiation and space‐dependent heat generating parameters strengthen the temperature distribution. Also, the heat transfer rate appreciably rises with the increment in Marangoni convection. The solution methodology and accuracy of the model is validated by generating the earlier outcomes for nonradiating nanofluid flow without heat source/sink.

Temperature-Dependent Electrical Conductivity and Thermal Radiation Effects on MHD Peristaltic Motion of Williamson Nanofluids in a Tapered Asymmetric Channel

ABSTRACTThis paper is intended for dealing with the peristaltic flow of an electrically conducting Williamson nanofluid in a tapered asymmetric channel through a porous medium with heat and mass transfer. In the current paper, temperature-dependent electrical conductivity formulation was introduced for the first time in peristaltic literature. The flow is pervaded by an oblique uniform magnetic field. The present investigation includes the influences of thermal radiation, Joule heat, viscous dissipation, Hall Current, 1st order chemical reaction, and Dofour and Soret numbers. Current problem is reformulated under the molds of low Reynolds number and long wavelength approximation. Afterwards, semi analytical solutions have been evaluated for the distributions of velocity, temperature, nanoparticle concentrations as well as longitudinal pressure gradient. Solutions can be obtained by using multi-step differential transform method (MS-DTM), a reliable and powerful technique that improve accuracy and overcome drawbacks raised in using the standard differential transform method (DTM). Detailed comparisons have been made at different values of 𝑥 through graphs by Ms-DTM. The graphically results were prepared to visualize the effects of various physical parameters of interest. The semi-analytical results had shown that, as the thermal radiation increases, the nanoparticles diameter and concentration of fluid increase (thermal radiation is a decreasing function in temperature when the temperature decreases the diameter of the nanoparticles increases i.e. the volume of nanoparticle and its concentration increases and become more effective near to tumor tissues). Consequently, it can be used as agents for radiation therapy, generate localized raises in radiation doses and selectively target tumor cells for localized damage (Radiotherapy of oncology).

The effects of thermal radiation on the flow of a reactive hydromagnetic heat generating couple stress fluid through a porous channel

This research work examines the influence of thermal radiation on the flow of a reactive hydromagnetic couple stress fluid flowing through a passable channel under the drive of heat source. The analytical expressions for the momentum and heat transfer are obtained to find the entropy generation rate using the modified Adomian decomposition method (mADM). The results are correlated with previously obtained results in the bid to ascertain and verity the efficacy of the mADM and mostly for end users to be able to predict the safe and unsafe situations. In addition to that, the effects of thermal radiation and other thermophysical parameters on fluid motion, energy transfer and rate of entropy generation are shown and discussed in tables and graphs.

Numerical analysis of MHD flow and nanoparticle migration within a permeable space containing Non-equilibrium model

This article deals with the numerical simulation to examine the significant effects of MHD flow and nanoparticle migration inside a permeable space including two temperature model. For more physical situation, thermal radiation influence is considered. Viable transformation is assumed to alter the governing set of PDEs into dimensionless form. CVFEM was adopted to model this article. Impacts of radiation parameter, Rayleigh number (103 <Ra < 104), nanofluid–solid interface factor (10 <Nhs <1000), Hartmann number (0 <Ha < 20) and nanoparticles’ shape (3 <m < 5.7) on nanofluid behavior were demonstrated. Outcomes depict that stronger convection can be obtained with augmenting in shape factor. Average Nusselt number increases as enhancing the buoyancy and radiation effect whereas decreases as enhancing nanofluid–solid interface factor and Hartmann number. Comparison of the numerical outputs achieved by means of CVFEM with published data was also deliberated. It is evident that the applied approach is very accurate to investigate solution of the discussed problem.

Theoretical and mathematical analysis of entropy generation in fluid flow subject to aluminum and ethylene glycol nanoparticles

BackgroundHere we have conducted a magnetohydrodynamic (MHD) flow of viscous material with alumina water and ethylene glycol over a stretched surface. The flow is discussed with and without effective Prandtl number. MHD liquid is considered. Electric field is absent. Effect of uniform magnetic field is taken in the vertical direction to the surface. Influence of thermal radiation as well as Joule heating are taken into account for both aluminum oxide-water and aluminum oxide-Ethylene glycol nanofluids. Velocity slip and melting heat effects are considered. MethodsThe nonlinear flow expressions are numerically solved via ND-solve technique (built-in-Shooting). ResultsThe physical impacts of flow variables like mixed convection parameter, magnetic parameter, Reynold number, Eckert number, melting parameter and heat source/sink parameter are graphically discussed. Moreover, entropy generation (irreversibility) and Bejan number are discussed graphically through various flow variables. Physical quantities like skin friction coefficient and Sherwood and Nusselt numbers are numerically calculated and discussed through Tables. ConclusionsImpact of magnetic and slip parameters on the velocity field show decreasing behavior for both effective and without effective Prandtl number. Temperature field increases for both effective and without effective Prandtl number for higher values of magnetic and radiative parameters. Entropy number is an increasing function of Reynolds number while Bejan number shows opposite impact against Reynolds number. Moreover, heat transfer rate upsurges versus larger melting and radiative parameter.

Thermal slip and radiative heat transfer effects on electro‐osmotic magnetonanoliquid peristaltic propulsion through a microchannel

AbstractA mathematical study is described to examine the concurrent influence of thermal radiation and thermal wall slip on the dissipative magnetohydrodynamic electro‐osmotic peristaltic propulsion of a viscous nanoliquid in an asymmetric microchannel under the action of an axial electric field and transverse magnetic field. Convective boundary conditions are incorporated in the model and the case of forced convection is studied, that is, thermal and species (nanoparticle volume fraction) buoyancy forces neglected. The heat source and sink effects are also included and the diffusion flux approximation is employed for radiative heat transfer. The transport model comprises the continuity, momentum, energy, nanoparticle volume fraction, and electric potential equations with appropriate boundary conditions. These are simplified by negating the inertial forces and invoking the Debye–Hückel linearization. The resulting governing equations are reduced into a system of nondimensional simultaneous ordinary differential equations, which are solved analytically. Numerical evaluation is conducted with symbolic software (MATLAB). The impact of different control parameters (Hartmann number, electro‐osmosis parameter, slip parameter, Helmholtz–Smoluchowski velocity, Biot numbers, Brinkman number, thermal radiation, and Prandtl number) on the heat, mass, and momentum characteristics (velocity, temperature, Nusselt number, etc) are presented graphically. Increasing Brinkman number is found to elevate temperature magnitudes. For positive Helmholtz–Smoluchowski velocity (reverse axial electrical field) temperature is strongly reduced, whereas for negative Helmholtz–Smoluchowski velocity (aligned axial electrical field), it is significantly elevated. With increasing thermal slip, nanoparticle volume fraction is also increased. Heat source elevates temperatures, whereas heat sink depresses them, across the microchannel span. Conversely, heat sink elevates nanoparticle volume fraction, whereas heat source decreases it. Increasing Hartmann (magnetic) parameter and Prandtl number enhance the nanoparticle volume fraction. Furthermore, with increasing radiation parameter, the Nusselt number is reduced at the extremities of the microchannel, whereas it is elevated at intermediate distances. The results reported provide a good insight into biomimetic energy systems exploiting electromagnetics and nanotechnology, and, furthermore, they furnish a useful benchmark for experimental and more advanced computational multiphysics simulations.

Semi Analytical Solution of Steady Burgers' Nanofluid Flow Between Parallel Channels with Heat Generation/Absorption Under the Influence of Thermal Radiation

Semi Analytical Solution of Steady Burgers' Nanofluid Flow Between Parallel Channels with Heat Generation/Absorption Under the Influence of Thermal Radiation

An analytical approach to the metal and metallic oxide properties of Cu–water and $$\hbox {TiO}_{2}$$–water nanofluids over a moving vertical plate

An analysis was carried out to study the flow phenomena of an unsteady, electrically conducting, water-based nanofluid embedded with a porous matrix over a moving / stationary plate. The effects on the nanofluid flow were observed by taking copper (Cu) and titanium oxide $$(\hbox {TiO}_{2})$$ nanoparticles. The crux of the investigation is to examine the influence of thermal radiation, radiation absorption parameter accounted for in the energy equation. The first-order chemical reaction was also taken care of by incorporating it into the solutal transfer equation. Closed form solution holds good for nonlinear coupled partial differential equations. Solutions of these equations are obtained by employing Laplace transform technique. The effects of parameters such as magnetic parameter, porous matrix, thermal and mass buoyancy parameters, thermal radiation, heat absorption parameter, radiation conduction parameter, Prandtl and Schmidt numbers and the homogeneous chemical reaction are shown via graphs. The results for the physical quantities of interest such as the rate of shear stress and the rate of heat and mass transfer coefficients are also obtained and presented through graphs. Observing these, the emerging role of a few parameters is elaborated in the results and discussion section.

Numerical study of thermal radiation and suction effects on copper and silver water nanofluids past a vertical Riga plate

PurposeThe purpose of this paper is to explore the flow of Cu-water and Ag-water nanofluids past a vertical Riga plate. The plate is infinite in height and has zero normal wall flux through its surface. Influence of thermal radiation, slip, suction and chemical reaction on the flow characteristics are reported.Design/methodology/approachNon-dimensional forms of the flow governing equations are obtained by means of a set of similarity transformations. Numerical solution is obtained with the help of fourth-fifth-order Runge–Kutta–Fehlberg method with shooting procedure. Comparison of solution profiles of Cu-water and Ag-water nanofluids are presented graphically and with the help of tables. Influence of pertinent parameters on skin friction and heat transfer rate is also reported.FindingsResults reveal that the skin friction coefficient is more prominent in the case of Ag-water nanofluid for an increase in thermal radiation and volume fraction. The role of suction and slip is to increase velocity but decrease the temperature in both nanofluids. Temperature and velocity of both nanofluids increase as volume fraction and thermal radiation values are augmented. Heat transport increases with thermal radiation. Region near the plate experiences rise in nanoparticle concentration with an increase in chemical reaction parameter.Originality/valueA complete investigation of the modeled problem is addressed and the results of this paper are original.

Magnetohydrodynamic flow of dissipative casson-carreau nanofluid over a stretching sheet embedded in a porous medium under the influence of thermal radiation and variable internal heat generation

Magnetohydrodynamic flow of dissipative casson-carreau nanofluid over a stretching sheet embedded in a porous medium under the influence of thermal radiation and variable internal heat generation

Enhancement of heat transfer in a convergent/divergent channel by using carbon nanotubes in the presence of a Darcy–Forchheimer medium

This article explores the influence of thermal radiation on the flow and heat transfer of single-walled carbon nanotubes over both a convergent and divergent channel. Flow is induced due to a Darcy–Forchheimer medium. Further, the heat transfer mechanism is analyzed in the presence of a thermal radiation process. Guided by some appropriate similarity transformations, the fundamental PDEs are converted into a self-similar system of coupled non-linear ODEs. The findings are obtained with the help of the Runge–Kutta-45-based shooting method. The roles of the Reynolds number, porosity parameter, inertia coefficient parameter, Prandtl number and radiation parameter are presented graphically. Results are displayed and show that the rate of heat transfer is higher in a divergent channel as compared to a convergent channel.

Radiative squeezing flow of unsteady magneto-hydrodynamic Casson fluid between two parallel plates

Present numerical study examines the heat and mass transfer characteristics of magneto-hydrodynamic Casson fluid flow between two parallel plates under the influence of thermal radiation, internal heat generation or absorption and Joule dissipation effects with homogeneous first order chemical reaction. The non-Newtonian behaviour of Casson fluid is distinguished from those of Newtonian fluids by considering the well-established rheological Casson fluid flow model. The governing partial differential equations for the unsteady two-dimensional squeezing flow with heat and mass transfer of a Casson fluid are highly nonlinear and coupled in nature. The nonlinear ordinary differential equations governing the squeezing flow are obtained by imposing the similarity transformations on the conservation laws. The resulting equations have been solved by using two numerical techniques, namely Runge-Kutta fourth order integration scheme with shooting technique and bvp4c Matlab solver. The comparison between both the techniques is provided. Further, for the different set physical parameters, the numerical results are obtained and presented in the form of graphs and tables. However, in view of industrial use, the power required to generate the movement of the parallel plates is considerably reduced for the negative values of squeezing number. From the present investigation it is noticed that, due to the presence of stronger Lorentz forces, the temperature and velocity fields eventually suppressed for the enhancing values of Hartmann number. Also, higher values of squeezing number diminish the squeezing force on the fluid flow which in turn reduces the thermal field. Further, the destructive nature of the chemical reaction magnifies the concentration field; whereas constructive chemical reaction decreases the concentration field. The present numerical solutions are compared with previously published results and show the good agreement.

Impact of Thermal Radiation and Heat Source/Sink on MHD Time-Dependent Thin-Film Flow of Oldroyed-B, Maxwell, and Jeffry Fluids over a Stretching Surface

In this study paper, we examined the magnetohydrodynamic (MHD) flow of three combined fluids, Maxwell, Jeffry, and Oldroyed- B fluids, with variable heat transmission under the influence of thermal radiation embedded in a permeable medium over a time-dependent stretching sheet. The fluid flow of liquid films was assumed in two dimensions. The fundamental leading equations were changed to a set of differential nonlinear and coupled equations. For this conversion, suitable similarity variables were used. An optimal tactic was used to acquire the solution of the modeled problems. The convergence of the technique has been shown numerically. The obtained analytical and numerical consequences are associated graphically and tabulated. An excellent agreement was obtained between the homotropy analysis method (HAM) and numerical methods. The variation of the skin friction and Nusslet number and their influence on the temperature and concentration profiles were scrutinized. The influence of the thermal radiation, unsteadiness effect, and MHD were the main focus of this study. Furthermore, for conception to be physically demonstrated, the entrenched parameters are discussed graphically in detail along with their effect on liquid film flow.

Influence of thermal radiation on hot cluster decay rates and abundances

The influence of radiative cooling on the unimolecular decay rates of free, hot clusters and molecules with unspecified excitation energies is quantified. Two different regimes, defined by the magnitude of the energy of the photons emitted, are identified and the boundary between them is given. The boundary is determined in terms of the photon emission rate constants and thermal properties of the particles. Also the abundance spectra are calculated for the continuous cooling case, corresponding to small photon energies. The two regimes correspond to continuous cooling and single photon quenching of the unimolecular decay. The radiative effect can be parametrized by a redefinition of the time each individual cluster has available to undergo evaporation, expressed by an effective radiative time constant.

Buoyancy Effects on Unsteady MHD Chemically Reacting and Rotating Fluid Flow Past a Plate in a Porous Medium

An unsteady magnetohydrodynamic natural convection transfer of mass and heat flow over a vertical porous sheet under the influence of thermal radiation and thermo-diffusion effect. The dimensionless governing equations are solved analytically by employing Laplace transform technique. The impact of various physical parameters on momentum, energy and concentration are discussed and analyzed with the aid of graphs. Furthermore, the numerical values for local Skin friction, Nusselt number and Sherwood number are noted and examined. Increasing the values of thermal diffusion results in increasing of the concentration, but it decreases with Schmidt number. Skin friction reduces for increasing values of thermo-diffusion are discussed with the help of tables.

Variable Thermal Conductivity and Thermal Radiation Effect on the Motion of a Micro Polar Fluid over an Upper Surface

The intent of this analysis is to explore the influence of thermal radiation paired with variable thermal conductivity on MHD micropolar fluid flow over an upper surface. The novelty of the present model is to consider the fluid flow along an upper horizontal surface of a paraboloid of revolution (uhspr) with the porous medium. This physical phenomenon is described by a set of coupled non-linear ODEs by using suitable scaling analysis. The ODEs along with the boundary conditions are solved numerically. Influence of various flow parameters on momentum, thermal and concentration boundary layers is discussed graphically. It is noticed that the variable thickness of the surface has a leading consequence on the boundary layer progression along the surface. Moreover, the results of this study are not only useful for industrial applications but also present a basic understanding of the physical model.

An optimal analysis for Darcy–Forchheimer three-dimensional Williamson nanofluid flow over a stretching surface with convective conditions

The augmented thermal conductivity is significant in betterment of heat transfer behavior of fluids. A number of other physical quantities such as density, viscosity, and specific heat play the key role in fluid flow behavior. Investigators have shown that the nanofluids have not only superior heat conductivity but also have better convective heat transfer capability than the base fluids. In this article, the analysis of three-dimensional Williamson fluid has been carried out under investigation. The fluid flow is taken over a linear porous stretching sheet under the influence of thermal radiation. The transformed system of equations has been solved by homotopy analysis method. The impact of embedded parameters on the fluid flow has shown graphically. The velocity profile in x-direction is decreased with the augmented stretching, Williamson, coefficient of inertia, and porosity parameters. The velocity profile in y-direction is increased with the enlarged stretching parameter, while reduced with the augmented Williamson, coefficient of inertia, and porosity parameters. The temperature profile is increased with the enlarged stretching, radiation, thermophoresis, parameter and Brownian motion parameters, and Biot number while decreased with the increased Prandtl number. The concentration profile is increased with the increased thermophoresis parameter and Biot numbers, while decreased with the enlarged stretching and Brownian motion parameters.

Thermal radiation and variable electrical conductivity effects on MHD peristaltic motion of Carreau nanofluids: Radiotherapy and thermotherapy of oncology treatment

AbstractThis study intends to investigate the influences of thermal radiation and variable electrical conductivity on the MHD peristaltic flow of Carreau nanofluids as the radiotherapy and thermotherapy are required for cancer treatment. Formulation of temperature‐dependent electrical conductivity is introduced for the first time in the peristaltic literature. The related equations of momentum, mass, and concentration are reformulated using lubrication approximations (ie, tiny or zero Reynolds number and long wavelength). These simplified equations are solved numerically with the aid of Parameteric‐NDSolve. Results for velocity, temperature, and concentration distributions are obtained in three‐dimensional analytical forms. The streamline graphs are offered in the terminus, which elucidate the trapping bolus phenomenon. A “special case” of our results offered to get the solutions over certain contours for the behaviors of velocity, temperature, and nanoparticle concentration. It is found that the magnetic nanoparticles acquire more energy at high temperature, enabling them to destroy and damage tumors tissues (thermotherapy of oncology). Radiation is the reason for spreading the energy, that is, the energy of all the fluid nanoparticles does not continue with the same value. Therefore, in cancer treatment, doctors use high doses of radiation to cure cancer cells and prevent it from returning (radiotherapy of oncology).

Influence of thermal radiation on peristaltic blood flow of a Jeffrey fluid with double diffusion in the presence of gold nanoparticles

Abstract This study considers the influence of thermal radiation on peristaltic motion with double diffusive convection of gold nanoparticles through an asymmetric channel under the long wavelength and low Reynolds number assumption. The effect of thermal radiation and double diffusion is an important area of medical research due to its application to the public health. Infrared radiation techniques are used to treat many skin-related diseases. They can also be used as a thermotherapy in some bones to enhance blood circulation. To restore the homeostasis of thermal regulation, infrared saunas can be utilized for medical treatment. In this work, the theory of peristaltic motion, the heat flux using a linear approximation, and thermal radiation are incorporated to consider the flow problem. This approximation is possible only where the temperature difference is small within the fluid flow. The mathematical model described includes partial differential and basic governing equations, which are solved by an analytical approximation known as the Homotopy Analysis Method (HAM). Solutions are obtained for velocity, temperature, solutal (species) concentration profile, and nanoparticle volume fraction profile. The results for velocity profile, temperature profile, pressure rise, solutal (species) concentration profile, and nanoparticle volume fraction for different physical parameters are discussed through graphs. The major outcome of this research is that the impact of thermal radiation on blood flow in the presence of gold nanoparticles increases the temperature profile, which may be assistive in destroying cancer cells during the drug delivery process.