Thermal Radiation Phenomena Research Articles

Modeling of Darcy–Forchheimer bioconvective Powell Eyring nanofluid with artificial neural network

Nano-engineering has recently grown to include the usages of nanoparticles in combination with base fluids to improve the thermal properties of pure fluids. Today’s industry focuses primarily on thermal machine efficiency, and nanomaterials are the key to achieving this goal. The slip and Darcy–Forchheimer phenomena are studied for bioconvective implementations in a Powell–Eyring nanofluid model confined by a stretching surface via artificial neural network in current study. During the research, the activation energy, convective boundary condition and thermal radiation phenomena are considered as novel impacts. The governing expressions are formulated according to fundamental rules. Numerical simulations using a Runge–Kutta fourth order technique via shooting procedure are used to obtain the solution and then applies artificial neural network. A data set has been created for various flow scenarios, and developed an artificial neural network model to predict skin friction coefficient, local Sherwood number, local motile density of microorganisms and local Nusselt number values . The results of the study showed that the developed artificial neural network models can make predictions with very low error, not exceeding 0.53% on average.

Numerical simulation of Cattaneo–Christov heat flux model in a porous media past a stretching sheet

This analysis investigates the impact of aligned magnetic field fluid flow of nanofluid past a nonlinear porous stretching sheet. Cattaeno–Christov heat flux model is considered to investigate the heat transport mechanism in the presence of Joule heating, thermal radiation, internal heating, viscous dissipation, thermophoresis and Brownian motion phenomena. Moreover, mass transport analysis is also carried out in the company of chemical reaction parameter. The governing nonlinear partial differential equations are converted into a system of dimensionless ordinary differential equations by introducing the similarity transformations. Numerical solution is obtained by shooting approach together with RK-4 technique and Newton's method. To study the physical insight of pertinent flow parameters, graphical illustration is prepared. These results are displayed in the form of velocity profile, temperature profile, concentration profile, wall shear stress, and wall heat transfer. It is graphically seen that the flow permeability parameter is directly proportional to the fluid temperature and inversely proportional to the flow velocity. Further, Local Nusselt number increases with variation in the relaxation time parameter.

Numerical Study of Thermal Radiation Phenomenon and Its Influence on Amelioration of the Heat Transfer Mechanism through MHD Non-Newtonian Casson Model

The present study’s main focus is regarding the physical properties of a two-dimensional (2D) magneto-hydrodynamic boundary layer non-Newtonian Casson fluid flow that moves due to an exponentially expanding surface with a mixed convection heat transfer mechanism. In the hydrodynamic flow and heat transmission process, the combined impact of thermal radiation and magnetic field influence is explored. The internal heat generation owing to the fluid motion or a very fluid viscosity is not taken into account. The Chebyshev spectral method (CSM) is employed in this work due to its ability, accuracy, and ease of obtaining the solution for non-linear system of ordinary differential equations (ODEs). This method is an approximate method that can usually obtain the solution in a series form. The mixed convection impact is incorporated in our problem. The results are graphed to help comprehend the many physical parameters that arise in the problem. Graphical results uncover that the speed liquid stream is lessened when reinforcing both the Casson boundary and the Hartmann number, while converse attributes are applied for the Grashof number and the radiation boundary. Finally, a comparison of our current results with previously published work on several particular situations of the problem reveals that they are in excellent agreement.

Numerical study for improvement the cooling process through a model of Powell-Eyring fluid flow over a stratified stretching sheet with magnetic field

The spectral collocation method based on the Vieta-Lucas polynomials is introduced here for the flow of non-Newtonian Powell-Eyring fluid. The attentiveness is focused on some physical characteristics that emerge for numerical simulation of flows with thermal radiation, magnetic field, and slip velocity phenomenon. In addition, the most significant-physical assumptions to handle in this study are the presence of the thermal stratification phenomenon and the handling of the heat generation term in the energy equation. The Vieta-Lucas spectral collocation method is implemented to present an approximate formula for the n-order derivative and solve numerically the proposed model. This method is employed to convert the system of ODEs that describes the problem to a non-linear system of algebraic equations. This system is constructed as a constrained optimization problem and optimized to get the unknown coefficients of the series solution. We state some theorems to study the convergence of the method. The results reveal that raising the viscosity parameter or the slip velocity parameter reduces the velocity distribution, but increasing the heat generation parameter or thermal conductivity parameter increases the temperature distribution.

HALL AND ION SLIP EFFECTS ON MHD BIOCONVECTIVE EYRING-POWELL NANOFLUID FLOW PAST A SLIPPERY SHEET UNDER POROUS MEDIUM CONSIDERING JOULE HEATING AND ACTIVATION ENERGY

This article investigates the Hall and ion slip effects on steady, incompressible, and bioconvective three-dimensional flow of Eyring-Powell nanofluid past a convectively heated stretching sheet placed in a uniform porous medium considering viscous dissipation and Joule heating. As per authors' knowledge, no such study is reported yet in the literature. Suitable similarity transformations are used to metamorphose the governing PDEs into a system of ODEs. The obtained nonlinear equations are solved numerically with the help of the bvp4c solver in MATLAB. The behaviors of various flow parameters on velocity, temperature, concentration, and microorganisms concentration fields are explained and exhibited through figures. Also, the variations in coefficients of local skin-friction, Nusselt, Sherwood, and motile numbers for sundry parameters are clarified and presented in the tabular form. Moreover, the acquired results are checked with the previously described results for a particular case of the present problem and a superb correlation is spotted from the comparison. The graphs exhibit that Hall and ion slip effects have the tendency to enhance the flow field. Moreover, there is a hike in the temperature profile due to the viscous dissipation, Joule heating, and thermal radiation phenomena. The local Sherwood number is reduced with respect to chemical reaction and activation energy.

Bioconvection Mangnetohydrodynamic Tangent Hyperbolic Nanofluid Flow with Quartic Chemical Reaction Past a Paraboloid Surface

In this numerical study, the effect of quartic autocatalysis type of chemical reaction, buoyancy force and thermal radiation phenomenon and magnetic effect on tangent hyperbolic nanofluid past an upper horizontal surface of a paraboloid has been studied. By considering the Buongiorno model approach, a diffusion of unequal coefficients in the presence of gyrotactic microorganism is discussed. Implementation of microorganism's idea is used to stabilize the nanoparticles through bioconvection. The modeled PDEs of the problems are converted into nonlinear ODEs with the assistant of the similarity transformations. To tackle nonlinear ODEs, MATLAB package bvp4c is used. In addition, a hallmark of the Matlab code with the reported results in the literature is achieved by benchmarking. The variations in motion, concentration, temperature, and motile density due to sundry parameters have been analyzed in-depth via graphs. Our analysis shows that the density profile of motile of microorganism is hiked with an increment in the bioconvection Rayleigh number but decreases for higher thermal Grashof number.

Effect of Hole Configuration on Heat Transfer through a Hollow Block Subjected to Solar Flux

In this paper, some effort is provided to optimize the geometry of a concrete hollow brick (used in the construction of building roofs) in order to increase the related thermal resistance, thereby reducing energy consumption. The analysis is conducted for three different configurations of the hollow concrete bricks. Coupling of conduction, natural convection and thermal radiation phenomena is considered. Moreover, the flows are assumed to be laminar and two-dimensional for the whole range of parameters examined. The conservation equations are solved by a finite difference method based on the control volumes approach and the SIMPLE algorithm for velocity-pressure coupling. The results show that the aspect ratio affects neither the nature of the fluid flow nor the number of convective cells. However, the extension of the circulation cells increases with this parameter. Moreover, the cavities with a large aspect ratio lead to significant reductions in the heat transfer through the hollow block, these reductions reaching approximately 14%.

Flow and Melting Thermal Transfer Enhancement Analysis of Alumina, Titanium Oxide-Based Maxwell Nanofluid Flow Inside Double Rotating Disks with Finite-Element Simulation

The energy produced by the melting stretching disks surface has a wide range of commercial applications, including semi-conductor material preparation, magma solidification, permafrost melting, and frozen land refreezing, among others. In view of this, in the current communication we analyzed magnetohydrodynamic flow of Maxwell nanofluid between two parallel rotating disks. Nanofluids are important due to their astonishing properties in heat conduction flows and in the enhancement of electronic and manufacturing devices. Furthermore, the distinct tiny-sized particles and in the Maxwell water-based fluid for enhancing the heat transfer rate are analyzed. The heat equation is developed in the occurrence of thermal radiation. The influences of melting impacts are incorporated. The mathematical model is developed in the form of partial differential expressions then converted to ordinary differential equations by employing tool of similarity variables. Finite element method (FEM) is chosen for solving the nonlinear governing ordinary differential equations (ODEs) with necessary conditions. The consequence of flow parameters against the velocity profiles and heat transport field is considered. The noted novelty of this communication is to discuss the thermal transfer of Maxwell nanofluid model through double stretching disks with thermal radiation and melting phenomenon. Further, /water and /water are considered in the modeling.

Turbulent mixed convection of air in a cavity with a heat-conducting inner solid: Effect of surface radiation and thermal diffusivity on heat transfer and exergy destruction

The study of natural and forced turbulent convection of heat has been essential to improving the design parameters of several engineering applications. However, few works have described the simultaneous effect of turbulence and thermal radiation phenomena on heat transfer and exergy destruction in cavities with inner solid bodies. This work investigates the turbulent mixed heat convection of air and the surface thermal radiation in a cavity with a heat-conducting square solid at its center through computational modeling. A turbulent k-ε model with damping functions and temperature-variable thermal properties are used for the air, while the local exergy destruction is computed by a direct method for turbulent flows. The effects of turbulence and surface thermal radiation are analyzed through the variation of the Grashof (108 ≤ Gr ≤ 1010) and Richardson (0.1 ≤ Ri ≤ 10) numbers, the emissivity of the surfaces (0 ≤ ∈ ≤ 0.9) and the thermal diffusivity ratio between solid and fluid (1 ≤ R ≤ 103). The main results indicate that the increment of Ri notably changes the magnitude and distribution of velocities and temperatures, increasing from 30% to 300% the maximum dimensionless velocity. The maximum temperatures in the cavity are reduced by 30% when thermal radiation is considered, resulting in weaker buoyancy-driven flows. The increment of the emissivity increases up to 5 times the value of the dimensionless heat transfer at the inner-solid surfaces, Nusselt number Nu¯, and decreases from 45% to 75% the total exergy destroyed (XdT) in the cavity. On the contrary, the increment of R only produces variations lower than 8% of the Nu¯ and the XdT for all the cases investigated.

Chebyshev collocation-optimization method for studying the Powell–Eyring fluid flow with fractional derivatives in the presence of thermal radiation

In this work, a mathematical model of the fractional-order in non-Newtonian Powell–Eyring fluid flow (PEFF) and heat transfer is presented and solved numerically. The set of nonlinear differential equations in terms of velocity, temperature which describes our proposed problem is tackled through the spectral collocation method based on Chebyshev polynomials of the third kind. This method reduces the presented model to a nonlinear system of algebraic equations. This system is constructed as a constrained optimization problem and optimized to get the unknown coefficients of the series solution. The effects of the thermal radiation, Powell–Eyring parameters; suction parameter and Prandtl number on the PEFF are discussed. The numerical values of the dimensionless velocity and temperature are depicted graphically. The results show that the given procedure is an easy and efficient tool to investigate the solution of such models. Some of findings of this important work help to govern the velocity and the rate of heat transportation through the boundary layer. At the same time, this study highlights many applications in fields of engineering and industry, where the quality of the desired product depends on the rate of heat transfer, thermal radiation phenomenon, and the composition of the material used, and manufacturing processes.

Darcy–Forchheimer higher-order slip flow of Eyring–Powell nanofluid with nonlinear thermal radiation and bioconvection phenomenon

Recently, nanoengineering has evolved to utilize nanoparticles along with base liquids to enhance the thermal attributes of pure liquids. The industry today also highly relies upon thermal machine performances, and the use of nanomaterials is the key to serve this purpose. In this research, the applications of the slip phenomenon are addressed for bioconvection applications in a non-Newtonian “Eyring–Powell” nanofluid model confined by a stretching sheet. The activation energy and nonlinear thermal radiation are taken as novel impacts during the study. The flow has been saturated by Darcy–Forchheimer porous space. The fundamental laws are attributed to formulate the governing expressions. The numerical simulations are continued employing a shooting scheme to obtain the solutions. The executive and novel physical importance of parameters that governs the flow is addressed for nanofluid velocity, temperature, concentration, and microorganisms’ profiles. The observations reveal that presence of slip parameter control the velocity but improve the heat and mass transportation phenomenon. The nanoparticles concentration increases with inertial forces and activation energy. Moreover, the bioconvection Lewis number declines the microorganism profile while increasing trend is noted for higher values of slip parameter.

A two‐component modeling for free stream velocity in magnetohydrodynamic nanofluid flow with radiation and chemical reaction over a stretching cylinder

AbstractThis analysis explores the influence of magnetohydrodynamic (MHD) nanofluid flow over a stretching cylinder with radiation effect in presence of chemically reactive species. The thermal radiation phenomenon is incorporated in the temperature equation. The mathematical modeling of the physical problem produces nonlinear set of partial differential equations corresponding to the momentum and energy equations that can be transformed into simultaneous system of ordinary differential equations with appropriate boundary conditions by applying similarity transformations. Shooting technique is used to solve the molded equations after adoption of Runge–Kutta–Fehlberg approach and ODE45 solver in MATLAB. A parametric analysis has been carried out to investigate the impacts of physical parameters that are considered in the current study. The attractive pattern studied the consequence of Brownian motion along with thermophoresis parameter. The outcomes of prominent fluid parameters, especially heat radiation, Lewis number, free stream velocity, chemical reaction, thermophoresis, and Brownian motion on the concentration, temperature, as well as velocity have been examined and are displayed through graphs and tables. The present study reveals that the temperature phenomenon enhances with an increase in radiation parameter, while nanoparticle concentration phenomenon reduces with an increase in chemical reaction parameter.

Bioconvection due to gyrotactic microbes in a nanofluid flow through a porous medium

The addition of gyrotactic microbes in the nanoparticles is essential to embellish the thermal efficiency of many systems such as microbial fuel cells, bacteria powered micro-mixers, micro-volumes like microfluidics devices, enzyme biosensor and chip-shaped microdevices like bio-microsystems. Porous media also plays a pivotal role in augmentation of the thermal efficiency. Our approach in the present work is to offer a novel study of bioconvection due to gyrotactic microbes in a nanofluid flow comprising thermal radiation within a porous media over a nonlinear shrinking/stretching surface. The entire coupled system involving nonlinear equations is tackled by means of Successive over Relaxation technique. The impacts of the involved parameters on the flow, motile microbes diffusion rate, mass and heat transfer rates are examined and shown through diagrams and tables. Comparisons with graphical and tabular data are provided and observed to be in a good agreement. Numerical results evidently point out that the motile microbes parameter and the bioconvection Peclet number elevate the motile microorganisms’ density whereas the thermal radiation phenomenon enhances the temperature.

Insight into the dynamics of magneto-casson hybrid nanoliquid caused by a plate rotation

PurposeThis paper aims to present the analytical investigation on an unsteady magneto-convective rotation of an electrically conducting non-Newtonian Casson hybrid nanoliquid past a vertical porous plate. The effects of thermal radiation, heat source/sink and hydrodynamic slip phenomenon are also taken into account. Ethylene glycol (EG) is adopted as a base Casson fluid. The Casson fluid model is accounted for to describe the rheological characteristics of non-Newtonian fluid. EG with copper and alumina nanoparticles is envisaged as a non-Newtonian Casson hybrid nanoliquid. The copper-alumina-ethylene glycol hybrid nanoliquid is considered as the regenerative coolant.Design/methodology/approachThe perturbation method is implemented to develop the analytical solution of the modeled equations. Acquired solutions are used to calculate the shear stresses and the rate of heat transfer in terms of amplitudes and phase angles. Numerical results are figured out and tabled to inspect the physical insights of various emerging parameters on the pertinent flow characteristics.FindingsThis exploration discloses that the velocity profiles are strongly diminished by the slip parameter. Centrifugal and Coriolis forces caused by the plate rotation are found to significantly change the entire flow regime. The supplementation of nanoparticles is to lessen the amplitude of the heat transfer rate. A comparative study is carried out to understand the improvement of heat transfer characteristics of Casson hybrid nanoliquid and Casson nanoliquid. However, the Casson hybrid nanoliquid exhibits a lower rate of heat transfer than the usual Casson nanoliquid.Practical implicationsThis proposed model would be pertinent in oceanography, meteorology, atmospheric science, power engineering, power and propulsion generation, solar energy transformation, thermoelectric and sensing material processing, tumbler in polymer manufacturing, etc. Motivated by such practical implications, the proposed study has been unfolded.Originality/valueThe novelty of this paper is to examine the simultaneous effects of the magnetic field, Coriolis force, suction/injection, slip condition and thermal radiation on non-Newtonian Casson hybrid nanoliquid flow past an oscillating vertical plate subject to periodically heating in a rotating frame of reference. A numerical comparison is also made with the existing published results under some limiting cases and it is found that the results are in good agreement with them. An in-depth review of the literature and the author’s best understanding find that such aspects of the problem have so far remained unexplored.

Zero‐mass flux and Cattaneo–Christov heat flux through a Prandtl non‐Newtonian nanofluid in Darcy–Forchheimer porous space

AbstractThe Darcy–Forchheimer Prandtl fluid flow due to moving sheet is described here. The familiar energy transfer model, namely, the Cattaneo–Christov model of heat transportation, is adopted under thermal radiation phenomenon. The Prandtl non‐Newtonian nanofluid is accounted as a functioning fluid. The functioning fluid flows in Darcy–Forchheimer porosity space. The boundary‐layer and similarity variables are executed to reframe the mathematical expressions into simplified and single independent variable. Numerical solutions of nonlinear dimensionless expressions are calculated. The variations of distinct constraints on important quantities are demonstrated through tabular and pictorial forms. It is visualized that the velocity of non‐Newtonian nanofluid is enhanced significantly by incrementing the elastic parameter. Improving the thermophoretic and Brownian movement parametric values leads to higher profile of Prandtl nanofluid temperature.

Simulation of thermal radiation in a micropolar fluid flow through a porous medium between channel walls

Among numerous methods which have been employed to reinforce the thermal efficiency in many systems, one is the thermal radiation which is a mode of heat transfer. Another way to improve the thermal efficiency is the utilization of the porous media. The present work includes the study of micropolar flow with allowance for thermal radiation through a resistive porous medium between channel walls. The governing coupled partial differential equations representing the flow model are transmuted into ordinary ones by using the suitable dimensionless coordinates, and then, quasi-linearization is employed to solve the set of relevant coupled ODEs. Effects of physical parameters on the flow under different conditions, arose by varying the governing parameters, are scrutinized and discussed through tables and graphs. A comparison is associated with previously accomplished results and examined to be in an exceptional agreement. The culminations evidently disclose that the porosity parameter and the Reynolds number suppress the microrotation and velocity, while material parameters produce opposite effects. The thermal radiation phenomenon downturns the temperature curves and enhances the heat transfer rate on the lower wall of channel.

Quantum nonlinear mixing of thermal photons to surpass the blackbody limit.

Nearly all thermal radiation phenomena involving materials with linear response can be accurately described via semi-classical theories of light. Here, we go beyond these traditional paradigms to study a nonlinear system that, as we show, requires quantum theory of damping. Specifically, we analyze thermal radiation from a resonant system containing a χ(2) nonlinear medium and supporting resonances at frequencies ω1 and ω2 ≈ 2ω1, where both resonators are driven only by intrinsic thermal fluctuations. Within our quantum formalism, we reveal new possibilities for shaping the thermal radiation. We show that the resonantly enhanced nonlinear interaction allows frequency-selective enhancement of thermal emission through upconversion, surpassing the well-known blackbody limits associated with linear media. Surprisingly, we also find that the emitted thermal light exhibits non-trivial statistics (g(2)(0) ≠ ~2) and biphoton intensity correlations (at two distinct frequencies). We highlight that these features can be observed in the near future by heating a properly designed nonlinear system, without the need for any external signal. Our work motivates new interdisciplinary inquiries combining the fields of nonlinear photonics, quantum optics and thermal science.

Hydromagnetic Carreau Nanoliquid in Frames of Dissipation and Activation Energy

The novel characteristics of magnetic field and entropy generation in mixed convective flow of Carreau fluid towards a stretched surface are investigated. Buongiornio nanoliquid model consists of thermophoresis and Brownian movement aspects is opted for analysis. Energy expression is modeled subject to thermal radiation and viscous dissipation phenomenon. Concentration by zero mass flux condition is implemented. Consideration of chemical reaction and activation energy characterizes the mass transfer mechanism. Total entropy generation rate and Bejan number is formulated. The utilization of transformation variables reduces the PDEs into non-linear ODEs. The obtained nonlinear complex problems are computed numerically through Shooting scheme. The impact of involved variables like local Weissenberg number, magnetic parameter, thermal radiation parameter, Brownian motion parameter, thermophoresis parameter, buoyancy ratio parameter, mixed convection parameter, Prandtl parameter, Eckert number, Schmidt number, non-dimensional activation energy parameter, chemical reaction parameter, Brinkman number, dimensionless concentration ratio variable, diffusive variable and dimensionless temperature ratio variable on velocity, temperature, nanoparticles concentration, entropy generation, Bejan number, surface drag force and heat transfer rate are examined through graphs and tables.

Thermal spin photonics in the near-field of nonreciprocal media

The interplay of spin angular momentum and thermal radiation is a frontier area of interest to nanophotonics as well as topological physics. Here, we show that a thick planar slab of a nonreciprocal material, despite being at thermal equilibrium with its environment, can exhibit nonzero photon spin angular momentum and nonzero radiative heat flux in its vicinity. We identify them as the persistent thermal photon spin and the persistent planar heat current respectively. With a practical example system, we reveal that the fundamental origin of these phenomena is connected to the spin-momentum locking of thermally excited evanescent waves. We also discover spin magnetic moment of surface polaritons that further clarifies these features. We then propose an imaging experiment based on Brownian motion that allows one to witness these surprising features by directly looking at them using a lab microscope. We further demonstrate the universal behavior of these near-field thermal radiation phenomena through a comprehensive analysis of gyroelectric, gyromagnetic and magneto-electric nonreciprocal materials. Together, these results expose a surprisingly little explored research area of thermal spin photonics with prospects for new avenues related to non-Hermitian topological photonics and radiative heat transport.

Entropy analysis of SWCNT & MWCNT flow induced by collecting beating of cilia with porous medium

In this article, we considers the thermodynamics analysis of creeping viscous nanofluid flow in a horizontal ciliated tube under the effects of a uniform magnetic field and porous medium. Moreover, energy analysis is performed in the presence of an internal heat source and thermal radiation phenomena. The thermal conductivity of base fluid water is strengthened by considering the carbon nanotubes (CNTs). Mathematical formulation operated, results in a set of non-linear coupled partial differential equations. The governed differential system is transformed into an ordinary differential system by considering suitable similarity variables. Exact solutions in the closed form are computed for the temperature, momentum and pressure gradient profiles. In this study, special attention is devoted to the electrical conductivity of the CNTs. Streamlines patterns are also discussed to witness the flow lines for different parameters. Thermodynamics analysis shows that entropy of the current flow system is an increasing function of Brinkmann number, magnetic parameter, nanoparticle concentration parameter and Darcy number.