Effects Of Variable Thermal Conductivity Research Articles

Effect of variable thermal conductivity in semiconducting medium underlying an elastic half-space

Effect of variable thermal conductivity in semiconducting medium underlying an elastic half-space

MHD Maxwell dusty fluid in thermally stratified radiative flow with temperature-dependent thermal conductivity and Cattaneo-Christov model

It might be very important for the polymer processing industries to comprehend how Maxwell fluids behave on a stretched cylinder. Optimizing the extrusion and drawing processes can ensure the desired product qualities while avoiding faults. The objective of this study is heat transfer analysis on a Maxwell dusty fluid flow cylindrical surface with the Cattaneo-Christov concept. We immerse the cylinder in porous media, with a two-dimensional fluid regulating the flow. Our mathematical model further considers the effects of variable thermal conductivity, radiation, viscous and joule heating, magnetic field, thermal stratification, and slip velocity. Based on the presumptions, partial differential equations (PDE's) have been used to evolve the mathematical model. Using similarity transformations, the PDE's for heat and momentum for both phases are transformed into highly nonlinear ODE's.The numerical results have been obtained on these ordinary differential equations by using the RKF-45 method. This issue's main characteristic is that it examines the scenario's liquid and dust phases throughout. Results are given both visually and tabularly for the major parameters over a velocity, temperature, skin friction coefficient, and Nusselt number. When we compared our method to a previously published paper, we discovered a decent match. The findings, which were obtained for our system, show that the velocity and thermal gradient of both the phases of fluid and dust behave in an opposite trend in favor of rising Maxwell parameter, where the curvature parameter makes the rise in the same manner. Furthermore, the thermal transport profiles for both phases decline for the rising thermal time relaxation parameter.

Effects of Variable Thermal Conductivity on MHD Fluid Flow on Rotating Vertical Cone in the Presence of Darcy Forchheimer, Soret and Dufour Effects through a Porous Medium

This research investigated the effects of Variable Thermal Conductivity on MHD fluid on a Rotating Vertical Cone in the Presence of Darcy Forchheimer, Soret and Dufour effects through a porous medium. The system of nonlinear differential equations were transformed into first order differential equations and solved using shooting technique in Matlab package Bvp4c.Furthermore, the effects of various parameters over the main physical quantities are shown graphically and also extensively discussed. The result shows that Thermal conductivity increases Tangential Velocity, Temperature and decreases Normal Velocity. Dufour increases Tangential Velocity and decreases Normal Velocity. Radiation parameter R enhances Tangential Velocity and Temperature.

Variable thermal conductivity in context of Green‐Naghdi theory of thermo‐microstretch solids

AbstractThe present work aims to study the influence of variable thermal conductivity in generalized thermoelastic solid with microstretch within the framework of the Green‐Naghdi theory. The analytical methodology is adopted for obtaining exact expressions of displacement components, stresses, couple stresses, micro stress distribution and temperature distribution. The effect of variable thermal conductivity is illustrated graphically in two and three dimensions for the above physical quantities by taking different values of thermal conductivity.

Two-phase simulation of entropy optimized mixed convection flow of two different shear-thinning nanomaterials in thermal and mass diffusion systems with Lorentz forces

This research compares the momentum, thermal energy, mass diffusion and entropy generation of two shear thinning nanofluids in an angled micro-channel with mixed convection, nonlinear thermal radiation, temperature jump boundary condition and variable thermal conductivity effects. The RKF 45 approach was used to solve the Buongiorno nonlinear governing model. The effect of different parameters on the flow, energy, concentration, and entropy generating fields have been graphically illustrated and explained. The hyperbolic tangent nanoliquid has a better velocity than the Williamson nanofluid. The Williamson nanofluid has higher thermal energy and concentration than the hyperbolic tangent nanoliquid in the microchannel. The Grashof number, both thermal and solutal, increases the fluid flow rate throughout the flow system. The energy of the nanoliquid is reduced by the temperature jump condition, while the energy field of the nanoliquid is enhanced by the improving thermal conductivity value. The nanoliquids concentration rises as the Schmitt number rises. The irreversibility rate of the channel system is maximized by the variable thermal conductivity parameter.

Heat transfer analysis of Carreau–Yasuda nanofluid flow with variable thermal conductivity and quadratic convection

Abstract Brownian motions and Thermophoresis are primary sources of nanoparticle diffusion in nanofluids, having substantial implications for the thermo-physical characteristics of nanofluids. With such a high need, the 2D, laminar MHD (Magnetohydrodynamic) quadratic convective stream of Carreau–Yasuda nano liquid across the stretchy sheet has been reported. The flow is caused by surface stretching. The principal purpose of this extensive study is to enhance thermal transmission. The effects of variable thermal conductivity and heat source are considered as well. The governing boundary layer equations are transmuted using similarity parameters into a series of non-linear ODEs (ordinary differential equations). The bvp4c algorithm is adopted to fix the translated system numerically. The effects of prominent similarity variables over the temperature, velocity and concentration field are graphically visualized and verified via tables. It explored that fluid’s speed diminishes for the more significant inputs of the magnetic coefficient, Brownian motion coefficient and Prandtl number. The thermal efficiency is improved for larger values of thermophoretic constant, varying thermal conductance and heat-generating parameters. The concentration field has proved to be a decreasing function of nanofluid constants.

Unsteady micropolar nanofluid flow past a variable riga stretchable surface with variable thermal conductivity

In this study, we considered the flow of a micropolar fluid over a vertical Riga sheet. The non linear stretching sheet is considered. The effects of variable thermal conductivity and radiation on the Riga sheet are taken into account. Additionally, we also debated the Brownian motion and thermophoretic. To simplify the partial differential equations, we converted them into dimensionless ordinary differential equations using suitable similarity variables and solved dimensionless system numerically using the bvp4c function. The impact of some intended parameters on the dimensionless velocity, microrotation, temperature, and concentration distributions graphically are presented and the numerical outcomes of physical quantities like skin friction, Nusselt number, Sherwood number, and couple stress have been presented in tabular form. The micropolar parameter increased which increased the couple stress and friction at surface. Because, the fluid rotation increased which increased friction at surface and also increased the couple stress. The transfer of mass decayed and transfer of heat heightened by larger values of variable thermal conductivity. Thermal conductivity improved which improved the heat transfer phenomena, so transfer of heat at surface becomes larger while also reducing the transfer of mass.

Numerical Investigation of the Finite Thin Film Flow for Hybrid Nanofluid with Kerosene Oil as Base Fluid over a Stretching Surface along with the Viscous Dissipation and Variable Thermal Conductivity Effects

This study examines the flow and heat transfer of a finite thin layer of a hybrid nanofluid across an unstable stretching surface with varying thermal conductivity and viscous dissipation effects. A hybrid nanofluid model is considered to comprise two different types of nanoparticles, Go and Ag , with kerosene oil used as a base fluid. To study the phenomenon of thermal conduction, a modified version of Fourier’s law model is adopted because in the power-law model, the thermal conductivity depends on the velocity gradient. A system of nonlinear ordinary differential equations is obtained by considering the similarity transformations over the obtained rheological system of partial differential equations which is then tackled by a well-known numerical approach, i.e., the bvp4c MATLAB technique. The rheological impacts of the power-law index, solid volume fraction, film thickness, Eckert number, and modified Prandtl number on temperature and velocity fields are graphically discussed and illustrated. In the presence of nanoparticles, the temperature of the working fluid is enhanced and the power-law index has an inverse relation with the velocity of the hybrid nanofluid.

Effect of variable thermal conductivity of ternary hybrid nanofluids over a stretching sheet with convective boundary conditions and magnetic field

In this study, a partial velocity slip of the boundary layer flow and an analysis of the MHD two-dimensional ternary hybrid nanofluid with fluid based on polymers with variable thermal conductivity are conducted. On a stretching sheet with a convective boundary condition, the investigation was conducted. Model equations with boundary conditions were transformed into a set of ODEs in order to study the flow. The resulting system of equations was solved by using the Runge-Kutta fourth-order method in conjunction with the shooting method. A numerical analysis was done to determine the impact of several key factors on the system's heat transfer characteristics and flow field velocity. Computed the flow field's velocity and heat transfer properties by varying these physical parameters, then graphically displayed the results. Additionally, tables covered the local shear stress and rate of heat transfer respectively, describe the flow's resistance to motion and the rate of local heat transfer of ternary hybrid nanofluid. For a thorough comparison, the results were compiled in tables. Additionally, the results were compared to data already available for regular fluids, and it was discovered that there was a very high degree of agreement between the two sets of results. This raises confidence in the precision of their numerical computations. New findingsThe explicit formulas that have been derived make it simple to understand how changes in temperature-dependent thermal conductivity and nanoparticle volume fraction affect significant parameters, such as sk.fsdain friction and heat transfer rate, in the study of ternary hybrid nanofluids.

Effects of variable thermal conductivity and curvature parameter on the peristalsis of hybrid nanofluid through a curved channel with curvature dependent channel walls

This study focused on the peristaltic motion of hybrid nano-liquid via a curved geometry with curvature-dependent channel walls. The hybrid nanofluid is composed of alumina (Al2O3) nanoparticles mixed with multi-wall carbon nanotubes (MWCNTs) and suspended in thermal oil. This combination is based on an experimental examination conducted by Asadi et al. [58]. Keeping in view the industrial applications of such flows, the hybrid nanofluid thermal conductivity is considered to vary with temperature. Furthermore, heat sink/source is also taken into account in the energy equation. Lubrication approximation is utilized to simplify the flow problem. The resulting model is treated using a numerical scheme NDSolve based on the shooting method (“a built-in command in Mathematica”). The primary focus remains on analyzing the impacts of the curvature parameter, flow rate, and variable thermal conductivity parameter. Outcomes indicate that there is a critical “flow rate” value for such a type of channel. The thermal transfer rate increases with an improvement in the values of the curvature parameter. Furthermore, graphical results reveal that hybrid nanofluid’s temperature decreases for higher values of flow rate, while it rises with heat generation/absorption parameter. It is observed that temperature of the hybrid nanofluid increases as the values of curvature parameter improve. A higher flow rate reduces the rate of heat transfer. It is also noted that velocity profile remains constant at a flow rate value of 7.40. Moreover, the variable thermal conductivity has a remarkable impact on temperature profile.

Unsteady Magnetohydrodynamics (MHD) mixed convection flow over a cone with the effect of chemical reaction and viscous dissipation

This paper investigates the Magnetohydrodynamics (MHD) convective flow over a cone with the influence of viscous dissipation, variable viscosity, chemical reaction and variable thermal conductivity effects. Related equations are tackled by the Homotopy analysis method (HAM). The impacts of physical variables on concentration, velocity and temperature are presented through numerical tables and graphs. It is noticed that the heat transfer rate (Nusselt number) increases against Prandtl number. Similarly, the mass transfer rate (Sherwood number) increases against Schmidt number. Also, it is seen that skin friction in tangential and azimuthal direction increases against the buoyancy forces ratio parameter. Current results are validated with previous literature work.

Analysis of radiative MHD Carreau nanofluid flow with melting heat transfer and variable thermal conductivity

AbstractIn this work, we present the impacts of melting heat transfer phenomena on the steady, laminar, incompressible, two‐dimensional magnetohydrodynamic (MHD) Carreau nanofluid flow towards the stretching sheet. Additionally, in energy equation thermal radiation and variable thermal conductivity effects are also taken into consideration. By using similarity variables, governing non‐linear partial differential equations (PDEs) of the Carreau nanofluid flow model are transformed into dimensionless non‐linear ordinary differential equations (ODEs). Numerical solutions are then investigated and the results are illustrated through graphs and tables showing parameters effect on velocity, temperature, and concentration profiles of the fluid and on physical quantities including skin friction coefficient, Nusselt and Sherwood numbers, respectively. From the analysis, it is found that boosting melting heat transfer parameter leads to increasing behavior in velocity and concentration distributions, while the opposite trend is noticed for temperature distribution. Numerical results are found in close agreement and are accurate by carrying out its comparison with previous results for skin friction coefficient with different magnetic parameters while keeping other parameter values constant.

Thermal case examination of inconstant heat source (sink) on viscous radiative Sutterby nanofluid flowing via a penetrable rotative cone

To improve heat transfer, this work provides a unique theoretical mathematical model of ternary hybrid nanofluid. In this analysis, the tri-hybrid nanoparticles TiO2, Al2O3, and AA7072 are submerged in ethylene glycol (EG), resulting in the mixture TiO2+Al2O3+AA7072/EG. The tri hybridity nanofluid is considered 3-D flowing via a rotate permeable cone embedded in Darcy-Forchheimer porousness material in the existence of fluctuating temperature generating (sink) and current radiate fluxing. The Keller box scheme (KBS) is exploited to resolve the liquid flowing and temperature equations numerically after converting them to ordinary differential equations employing similarity transformations. The results are graphed, and it is shown that the tri-hybrid nanofluid (THNF) has superior thermal conductance to the hybrid nanofluid (HNF) and that the fluid's velocity and temperature develop as a consequence of enlargement in thermal radiative fluxing and variable thermal conductivity effects. Raising values of De and Fr decline drag friction but drag friction coefficient values are improved as a result of positive variation in M,Re,ς, and λ. It is apparent that the rate of heat transference amplifies owing to magnification in QT, QE and Rd but the heat transfer rate diminishes due to magnification in Re and Fr. Incremental change in volume fraction of nanoparticles φ=0.005to0.03 delivers more heat in the case of tri-HNFs TiO2+Al2O3+AA7072 in contrast to ethylene glycol based TiO2+Al2O3 fluid. The optimal percentage error diminishes for the drag friction phenomenon from 1.4% up to 1.1% by adopting De from 1 to 1.5 and λ=0.5. The percentage error in terms of heat transfer rate is getting smaller from 3.6% to 3.0% because of a positive change in QT by keeping Rd=1.5.

Variable thermal conductivity in micropolar thermoelastic medium without energy dissipation possessing cubic symmetry

This investigation deals with the effect of variable thermal conductivity in a micropolar thermoelastic medium without energy dissipation with cubic symmetry. The normal mode technique is employed for obtaining components of physical quantities such as displacement, stress, temperature distribution and microrotation.

Modified Finite Element Study for Heat and Mass Transfer of Electrical MHD Non-Newtonian Boundary Layer Nanofluid Flow

Research into the effects of different parameters on flow phenomena is necessary due to the wide range of potential applications of non-Newtonian boundary layer nanofluid flow, including but not limited to production industries, polymer processing, compression, power generation, lubrication systems, food manufacturing, and air conditioning. Because of this impetus, we investigated non-Newtonian fluid flow regimes from the perspectives of both heat and mass transfer aspects. In this study, heat transfer of electrical MHD non-Newtonian flow of Casson nanofluid over the flat plate is investigated under the effects of variable thermal conductivity and mass diffusivity. Emerging problems occur as nonlinear partial differential equations (NPDEs) in opposition to the conservation laws of mass, momentum, heat, and species transportation. The shown problem can be recast as a set of ordinary differential equations by making the necessary changes. A modified finite element method is adopted to solve the obtained set of ODEs. The numerical method is based on Galerkin weighted residual approach, and Gauss–Legendre numerical integration is adopted in the modified finite element method application procedure. To clarify the obtained results, another numerical technique is employed to solve the reduced ODEs. With the help of error tables and the flowing behavior of complicated physical parameters on estimated solutions, this study graphically and tabulatively explains the convergence of analytic solutions. Comparing some of the obtained results with those given in past research is also done. From the obtained results, it is observed that the velocity profile escalates by improving the electric parameter. Our intention is for this paper to serve as a guide for academics in the future who will be tasked with addressing pressing issues in the field of industrial and engineering enclosures.

Numerical analysis of Darcy resistant Sutterby nanofluid flow with effect of radiation and chemical reaction over stretching cylinder: induced magnetic field

<abstract> <p>In this analysis, Sutterby nanofluid flow with an induced magnetic field at a nonlinear stretching cylinder is deliberated. The effects of variable thermal conductivity, Darcy resistance, and viscous dissipation are discussed. Thermal radiation and chemical reaction are considered to analyze the impact on the nonlinear stretching cylinder. The governing model of the flow problem is developed under the boundary layer approximation in terms of partial differential equations. Partial differential equations are transformed into ordinary differential equations by performing the suitable transformations. A numerical structure is applied to explain ordinary differential equations. The impact of each governing physical parameters on the temperature, concentration, skin friction, Sherwood, and Nusselt number is presented in graphs and tabular form. Increment in Prandtl number, which declined the curves of the temperature function. Temperature declined because the Prandtl number declined the thermal thickness as well as reduce the temperature of the fluid. Temperature curves showed improvement as Eckert number values increased because the Eckert number is a ratio of kinetic energy to the specific enthalpy difference between the wall and the fluid. As a result, increasing the Eckert number causes the transformation of kinetic energy into internal energy via work done against viscous fluid stresses.</p> </abstract>

Rotation, electromagnetic field, and variable thermal conductivity effects on free convection flow past an eternity vertical porous plate

AbstractThe present research may facilitate the reduction of the number of conversion steps required to include the low output voltages in an electrokinetic biomass process. Variable thermal conductivity and electroosmosis flow have already established great potential in the thermo‐elastic models of various manufacturing industries and have been widely used in energy technologies. As a result, the current framework investigates the characteristics of natural convection flow with the influence of variable thermal conductivity and electroosmosis over an eternity vertical porous plate. Coriolis forces and Hall current effects are considered in the momentum equations, and also thermal radiation and variable thermal conductivity are taken as energy equations. A linear chemical reaction parameter is used in the concentration equation. The equation of Poisson–Boltzmann is exploited to depict the electric potential characteristics within the accelerated plate medium. The pdepe command in Matlab software is used to figure out the numerical solutions to equations about momentum, energy, and concentration. The expressions of fluid transverse velocity, fluid axial velocity, fluid temperature, and concentration profiles are presented as numerical results and also derived vital relevant stream parameters diagrammatically, whereas the numerical values of primary skin friction, secondary skin friction, and Nusselt number are presented in tabular form for various values of pertinent flow parameters. The temperature rises as the strength of the thermal conductivity variable parameter increases. Also, as the values of the Taylor number and the thermal conductivity variable parameter go up, the primary velocity goes down. Similarly, secondary velocity increases in the opposite direction as the Taylor number and thermal conductivity variable parameter increase.

Effect of Variable Thermal Conductivity and Magnetic Field for the Generated Photo-Thermal Waves on Microelongated Semiconductor

A theoretical analysis of the dynamic impacts of a novel model in the microelongated-stimulated semiconductor medium is investigated. The influence of the magnetic field of the optically excited medium is taken into consideration according to the photothermal transport processes. The governing equations were created during the electronic (ED) and thermoelastic (TED) deformation processes. Thermal conductivity of the semiconductor microelongation medium is taken as temperature dependent. The interaction of thermal, microelongate, plasma, and mechanical waves is examined. Dimensionless formulae are used to solve the main equations in two dimensions (2D) using the harmonic wave method. The physical field equations have complete solutions when some conditions are applied to the semiconductor surface. The theoretical microelongated semiconductor model employed in this experiment was confirmed by comparing it to certain earlier studies. The numerical simulation for the principal physical field distributions is graphically displayed when silicon (Si) material is employed. The topic of the discussion was the impact of several factors, such as the magnetic field, thermal memory, and microelongation, on the propagation of waves for major fields.

The Effects of Variable Thermal Conductivity in Thermoelastic Interactions in an Infinite Material with and without Kirchhoff’s Transformation

In this paper, the problem of an unbonded material under variable thermal conductivity with and without Kirchhoff’s transformations is investigated. The context of the problem is the generalized thermoelasticity model. The boundary plane of the medium is exposed to a thermal shock that is time-dependent and considered to be traction-free. Because nonlinear formulations are difficult, the finite element method is applied to solve the problem without Kirchhoff’s transformations. In a linear case, when using Kirchhoff’s transformations, the problem’s solution is derived using the Laplace transforms and the eigenvalue approach. The effect of variable thermal conductivity is discussed and compared with and without Kirchhoff’s transformations. The graphical representations of numerical results are shown for the distributions of temperature, displacement and stress.

Influence of variable thermal conductivity and dissipation on magnetic Carreau fluid flow along a micro-cantilever sensor in a squeezing regime

Mathematical modeling of squeezing flows finds numerous applications in biological, mechanical, and medical engineering. Sensors feature such flows and can be effectively utilized to control vibrations and regulate lubrication. Magnetic fluids are critical to modern sensor systems. Micro-cantilevers are utilized in biomedical applications as biological, physical, or chemical sensors and operate via the detection of variations in the vibrational frequency or cantilever bending. Hence, a theoretical study is conducted to explore the dissipative flow and thermal characteristics in non-Newtonian boundary layer flow along a micro-cantilever sensor surface suspended in a squeezing regime between parallel plates. To achieve a more refined simulation, the effects of variable thermal conductivity and Joule magnetic dissipation are incorporated. The governing conservation equations for unsteady magnetic Carreau squeezing flow and heat transfer are rendered dimensionless and self-similar via appropriate scaling transformations. Emerging nonlinear coupled boundary value problem is then solved by using RK-4 method. The magnifying Weissenberg parameter decays the flow field. Skin friction is elevated with increasing Carreau power-law index and Weissenberg number. The novelty of the present study is the inclusion of dissipation and thermal conductivity variation effects which extends previous investigations and provides a more accurate appraisal of thermal characteristics in sensor squeezing flows.