Analysis of Joule heating and chemical reaction effects in electroosmosis peristaltic transport of couple-stress and micropolar fluids

This article features the reaction of electroosmosis peristaltic transport of combined couple-stress and micropolar fluid in an inclined asymmetric channel through a porous medium. Mathematical modeling is given in the presence of Joule heating, thermal radiation, and heat flux effects. The relevant equations are computed subject to long wavelength and small Reynolds number approximation. The coupled system resulting equations have been executed computationally to plot different effects graphically. A detailed analysis of the results is given through graphs. Graphs are plotted for velocity, temperature, concentration, and pumping characteristics. The impact of each significant parameter on flow, species, and thermal characteristics is enumerated in these studies. The influence of couple stress and electroosmosis parameters are also simulated. This problem is very significant to the discussion of chemical separation/fraternization procedures and bio-microfluidics devices for the resolution of the diagnosis.     

Joule heating impacts on MHD pulsating flow of Au/CuO-blood Oldroyd-B nanofluid in a porous channel

This article deals, the pulsating flow of blood carrying Au/CuO Oldroyd-B nanofluid through a porous channel with the effects of viscous dissipation, thermal radiation, and Joule (Ohmic) heating, and applied magnetic field. The perturbation technique is employed to get analytic solutions for flow variables. A comparison between analytical and numerical results shows a good agreement. The effect of various parameters is addressed extensively aided by pictorial results. The obtained results present that the velocity is reduced with the higher values of Hartmann number and volume fraction of nanoparticles. The temperature of nanofluid is enhanced with an enhancement of Eckert number and radiation parameter while it reduces with a rise in Hartmann number. Furthermore, the rise of the volume fraction of nanoparticles boosts up the rate of heat transfer.     

Solidification of electrically conducting liquid flow driven by shear and pressure gradients subject to viscous and Joule heating

Solidification of a liquid in motion driven by shear and pressure gradients occurs in many natural settings and technological applications. When the liquid is electrically conducting, its solidification rates can potentially be modulated by an imposed magnetic field. The shearing motion results in viscous dissipation and the Lorentz force induced by the magnetic field causes Joule heating of the fluid, which can influence the structure of the flow, thermal fields, and thereby the solidification process. In this study, a mathematical model is developed to study the combined effects of shear and pressure gradients in the presence of a magnetic field on the solidification of a liquid between two parallel plates, with one of them being insulated and under constant motion, and the other being cooled convectively and at rest. Under the quasi-steady assumption, closed-form semianalytical solutions are obtained for the instantaneous location of the solid–liquid interface, Nusselt number, and dimensionless power density as a function of various characteristic parameters such as the Hartmann number, pressure gradient parameter, Brinkman number, and Biot number. Furthermore, an interesting remelt or steady-state condition for the interfacial location is derived as arising from the competing effects of the solid side heat flux and viscous dissipation and Joule heating on the liquid side. The newly derived analytical results are shown to reduce to the various classical results in the limiting cases. A detailed systematic study is performed by the numerical solution of the semianalytical formulation, and the effects of different characteristic parameters on the solidification process are discussed.     

Influence of radiation and viscous dissipation on MHD heat transfer Casson nanofluid flow along a nonlinear stretching surface with chemical reaction

The present article investigates the influence of Joule heating and chemical reaction on magneto Casson nanofluid phenomena in the occurrence of thermal radiation through a porous inclined stretching sheet. Consideration is extended to heat absorption/generation and viscous dissipation. The governing partial differential equations were transformed into nonlinear ordinary differential equations and numerically solved using the Implicit Finite Difference technique. The article analyses the effect of various physical flow parameters on velocity, heat, and mass transfer distributions. For the various involved parameters, the graphical and numerical outcomes are established. The analysis reveals that the enhancement of the radiation parameter increases the temperature and the chemical reaction parameter decreases the concentration profile. The empirical data presented were compared with previously published findings.     

Numerical treatment of magneto Carreau nanofluid over a stretching sheet considering Joule heating impact and nonlinear thermal ray

In this essay, the magnetohydrodynamic flow of a Carreau nanoliquid upon a radiative stretching plate has been reviewed. The impacts of Joule heating and thermal ray are considered. The thermophoresis phenomenon and Brownian motion are applied to model nanoparticles (Buongiorno's model). Governing equations are solved numerically using Runge‐Kutta‐Fehlberg 4.5 after the transformation of partial differential equations into ordinary differential equations. In the obtained outcomes of investigating the impacts of different parameters on the change in velocity, concentration, and temperature profiles for two cases of shear‐thinning liquid and shear thickening liquid are reported as diagrams. Also, in the final segment of this essay, the impacts of diverse parameters on the skin friction coefficient and the local Nusselt number are investigated. The novel findings of current research illustrate that the values of local Nusselt number and surface drag force for shear thickening liquid are higher than shear‐thinning liquid. Also, the temperature profile has direct relationships with thermal radiation and magnetic field.     

Influence of Hall and Joule heating on a magnetic nanofluid (Fe3O4) flow on a rotating disk with generalized slip condition

This study analyzes Hall current and Joule heating effects on the ferro-nanofluid flow by the rotation of the disk incorporated with generalized slip condition. By using the well-known Von Karman transformation, formulated flow equations are modeled into ordinary differential equations. Numerical solutions of the governing flow equations are attained by utilizing the shooting method consolidated with the fourth-order Runge–Kutta scheme. The impacts of different parameters on skin friction coefficient, velocity, temperature, and Nusselt number are given in graphs and tables and investigated in detail. Furthermore, an association with formerly published articles is given and met in remarkable correspondence.     

Actions of viscous dissipation and Ohmic heating on bidirectional flow of a magneto-Prandtl nanofluid with prescribed heat and mass fluxes

The present contribution determines the impacts of viscous dissipation and Ohmic heating with magnetic coating on Prandtl nanofluid flow driven by an unsteady bidirectionally moveable surface. Random motion of nanoparticles and thermophoretic diffusion are elaborated through a two-phase nanofluid model. The novelty of the investigation is fortified by prescribed heat flux and prescribed mass flux mechanisms. The appropriate combination of variables leads to a system of strong nonlinear ordinary differential equations. The formulated nonlinear system is then tackled by an efficient numerical scheme, namely, the Keller–Box method. Nanoliquid-temperature and mass-concentration distributions are conferred through various plots with the impacts of miscellaneous-arising parameters. The rates of heat and mass transferences are also discussed through tables. The thermal states of the nanomaterial and mass concentration are reduced for incremental amounts of the unsteady factor, ratio parameter, elastic parameter, and Prandtl fluid parameter. Moreover, escalating amounts of the Brownian parameter, Eckert number, magnetic factor, and thermophoresis parameter enhances the temperature of the nanoliquid. An error analysis is also presented to predict the efficiency of the method used for the computational work.     

On the effectiveness of viscous dissipation and Joule heating on steady MHD flow and heat transfer of a Bingham fluid over a porous rotating disk in the presence of Hall and ion-slip currents

The combined effects of viscous dissipation and Joule heating on steady magnetohydrodynamics (MHD) flow of an electrically conducting viscous incompressible non-Newtonian Bingham fluid over a porous rotating disk in the presence of Hall and ion-slip currents is studied. An external uniform magnetic field is applied in the z-direction and the fluid is subjected to uniform suction. Numerical solutions are obtained for the governing momentum and energy equations. Results for the details of the velocity as well as temperature are shown graphically and the numerical values of the skin friction and the rate of heat transfer are entered in tables.     

The effect of Joule heating and viscous dissipation on the boundary layer flow of a magnetohydrodynamics micropolar-nanofluid over a stretching vertical Riga plate

Joule heating and viscous dissipation effects on the behavior of the boundary layer flow of a micropolar nanofluid over a stretching vertical Riga plate (electro magnetize plate) are considered. The flow is disturbed by an external electric magnetic field. The problem is formulated mathematically by nonlinear system of partial differential equations (PDEs). By using suitable variables transformations, this system is transformed onto a system of nonlinear ordinary differential equations (ODEs). The Parametric NDsolve package of the commercial software Mathematica is used to solve the obtained ODEs as well as the considered numerical results for different physical parameters with appropriate boundary conditions. Novel results are obtained by studying the stream lines flow around the plate in two and three dimensions. Moreover, the effects of the pertinent parameters on the skin friction coefficient, couple stress, local Nusselt, and Sherwood number are discussed. Special cases of the obtained results show excellent agreements with previous works. The results showed that as the magnetic field parameter increases the velocity of the boundary layer adjacent to the stretching sheet decreases. Also, for a productive chemical reaction near the sheet surface, the angular velocity decreases but opposite trend is observed far from the sheet surface. The importance of this study comes from its significant applications in many scientific fields, such as nuclear reactors, industry, medicine, and geophysics.     

MHD boundary layer of GO–H2O nanoliquid flow upon stretching plate with considering nonlinear thermal ray and Joule heating effect

This essay investigates a steady three‐dimensional laminar boundary layer flow of magnetohydromagnetic radiative of graphene oxide‐water nanofluid over an extensible surface in the attendance of couple stress, thermal ray, and Joule heating impact. Governing equations are solved numerically using the Runge‐Kutta‐Fehlberg 4.5 approach after the transformation of partial differential equations into ordinary differential equations. The main goal of this essay is to check the impacts of variations in the value of numerous parameters on the velocity along x and y‐axis directions () and temperature () profiles, and also on the local skin friction coefficient along x and y‐axis directions in the presence of couple stress (K > 0) and the lack of couple stress (K = 0) and local Nusselt number for the two modes of nonlinear () and linear () thermal ray. The results elucidate that the local Nusselt number for both and modes has a direct connection with radiation parameter (R) and Prandtl number (Pr) and an inverse relation with Eckert number (Ec) and Hartman number (Ha). In addition, the skin friction coefficient has an inverse relation with couple stress (K).     

The effects of Joule heating and variable thermal conductivity on peristaltic pumping of Jeffrey nanofluid in the presence of heat transfer

This investigation aims to study Hall's current effect on the peristaltic flow of a Jeffrey nanofluid with variable thermal conductivity in an inclined asymmetric channel. Joule heating and oblique magnetic field effects are taken into consideration. A system of ordinary differential equations is obtained under the approximation of low Reynolds number and long wavelength, which consists of momentum, energy, and concentration equations. The influences of penitent physical parameters on the distribution of velocity, temperature, and concentration have been discussed graphically. Streamline graphs are offered in the terminus, which elucidates the trapping bolus phenomenon. The resulting equations are solved numerically using the ND Solver technique. The thermal conductivity parameter causes the pressure gradient to increase while reducing the pressure rise. Our present model can be applied to physiological flow transportation in the veins with heat transfer.     

Magnetized impacts of Brownian motion and thermophoresis on unsteady squeezing flow of nanofluid between two parallel plates with chemical reaction and Joule heating

Present research article investigate the heat and mass transfer characteristics of unsteady magnetohydrodynamic Casson nanofluid flow between two parallel plates under the influence of viscous dissipation and first order homogeneous chemical reaction effects. The impacts of thermophoresis and Brownian motion are accounted in the nanofluid model to disclose the salient features of heat and mass transport phenomena. The present physical problem is examined under the presence of Lorentz forces to investigate the effects of magnetic field. Further, the viscous and Joule dissipation effects are considered to describe the heat transfer process. The non‐Newtonian behaviour of Casson nanofluid is distinguished from those of Newtonian fluids by considering the well‐established rheological Casson fluid model. The two‐dimensional partial differential equations governing the unsteady squeezing flow of Casson nanofluid are coupled and highly nonlinear in nature. Thus, similarity transformations are imposed on the conservation laws to obtain the nonlinear ordinary differential equations. Runge‐Kutta fourth order integration scheme with shooting method and bvp4c techniques have been used to solve the resulting nonlinear flow equations. Numerical results have been obtained and presented in the form of graphs and tables for various values of physical parameters. It is noticed from present investigation that, the concentration field is a decreasing function of thermophoresis parameter. Also, concentration profile enhances with raising Brownian motion parameter. Further, the present numerical results are compared with the analytical and semianalytical results and found to be in good agreement.     

Impact of Hall and Ion effects on MHD couple stress nanofluid flow through an inclined channel subjected to convective,hydraulic slip,heat generation,and thermal radiation

This project mainly concentrates on the numerical investigation of the Hall and Ion impact on couple stress nanofluid flow through an inclined microchannel considering the hydraulic slip and convective boundary conditions in the presence of radiative heat flux. The analysis has been made via assuming that the fluid is incompressible, electrically conducting, and viscous. The parameters of couple stress, convection, and heat generation have been employed. Different water‐based nanofluids containing $\text{Cu}\mathrm{,}\text{Ag}\mathrm{,}\text{Cuo}\mathrm{,}\text{Mo}{\mathrm{S}}_2\mathrm{,}\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3$, and $\text{Ti}{\mathrm{O}}_2$ are taken into account. To reduce the nonlinear system of ordinary differential equations, suitable nondimensional variables are applied to the governing equations. Then, this system is solved numerically utilizing the Runge‐Kutta‐Fehlberg fourth‐fifth‐order method along with the shooting technique. Maple software was employed to get numerical solutions. The results found that the fluid velocity is retarded for larger estimations of the Hall and Ion parameter. The drag force and the Nusselt number are diminished for higher estimations of the nanoparticle volume fraction and Brinkman number, respectively. Furthermore, it is noted that the nanoparticles have a maximum heat transfer rate as compared with the oxides of nanoparticles. The obtained results are compared with existing ones in a limiting case, and provide good agreement.     

Entropy generation minimization and nonlinear heat transport in MHD flow of a couple stress nanofluid through an inclined permeable channel with a porous medium,thermal radiation and slip

Irreversible losses and heat transport in a magnetohydrodynamic flow of a viscous, steady, incompressible, and fully developed couple stress Al₂O₃–water nanofluid through a sloping permeable wall channel with porous medium and under the effect of radiation heat flux and slip were analyzed. The fundamental equations were solved numerically by using Runge-Kutta together with the shooting technique and the results were in qualitative agreement with an exact solution obtained for a limit case. The impacts of couple stress, Darcy number, solid nanoparticle concentrations, conduction-radiation parameter, Hartmann number and hydrodynamic slip on flow, temperature, heat transport, and entropy production were examined. It was possible to achieve values of minimum entropy production not yet reported in previous studies. In this way, optimal values of couple stress and slip were obtained. The heat transport was also explored and optimal values of slip flow and conduction-radiation parameter with maximum heat transfer were found. Finally, in addition to the alumina, the distributions of velocity, temperature, and entropy generation in TiO₂–water and Cu–water were presented for different solid nanoparticle concentrations. It was obtained that the local entropy of TiO₂–water was lower than Cu–water and Al₂O₃–water in the channel bottom region while it was greater in the upper region.     

Impacts of variable thermal conductivity and mixed convective stagnation‐point flow in a couple stress nanofluid with viscous heating and heat source

The current study examines mixed (combined) convection stagnation‐point couple stress nanofluid over a stretched cylinder of variable thermal conductivity in the presence of viscous dissipation and internal heat source. The basic governing partial differential equations have been converted to coupled nonlinear differential equations by using adequate similarity transformations. By applying semi‐analytic technique (BVPh2.0), the equivalent ordinary differential equations are successfully solved and validated with a bvp4c solver. Graphs are presented to study the impact of various parameters on axial velocity, temperature, and volumetric nanofluid concentration profiles. The coefficient of skin friction (quantifying resistance) and the rate of heat and mass transfer on the surface due to flow variables are computed and explained. The axial velocity and momentum thickness are decreased with increasing couple stress parameter, whereas the reverse trend is noted with mixed convection and buoyancy ratio parameters. The temperature distribution increases for increasing Brownian motion and thermal conductivity parameter, whereas it decreases for increasing stagnation parameter.     

Soret,viscous dissipation,and thermal radiation effects on MHD free convective flow of Williamson liquid with variable viscosity and thermal conductivity

The flow model of heat and mass transport of a Williamson liquid through a porous stretching sheet with radiation, viscous dissipation, Soret effect, and chemical reaction has been explored. The motion starts from the slot to the free stream. The present study is unique, because it examines the flow of a Williamson fluid under the influence of variable viscosity and thermal conductivity. The Williamson fluid term as added to the momentum and energy equation is considered in a nonlinear form as compared with other studies in literature. The flow model is a set of coupled highly nonlinear partial differential equations that are simplified and lead to coupled nonlinear total differential equations by employing sufficient similarity variables. The simplified equations are later solved by utilizing the spectral homotopy analysis method. Our experiment shows that the injected variable viscosity, together with thermal conductivity, has a great impact on the fluid profiles. An increase in the Williamson parameter (β) leads to a decrease in the thickness of the hydrodynamic thermal layer. Our numerical calculations were compared with earlier published work, and they were discovered to be correct.     

Effects of Newtonian heating and thermal radiation on micropolar ferrofluid flow past a stretching surface: Spectral quasi‐linearization method

This study article addressesthe flow and heat transfer characteristics of a magnetite Fe₃O₄ micropolar ferrofluid flow past a stretching sheet. For practical interest, thermal radiation, Newtonian heating, and a heat source or sink are considered in this investigation. A useful Tiwari‐Das nanofluid model is considered to analyze the microstructure and inertial characteristics of the water‐based nanofluids containing iron oxide. The dimensionless nonlinear ordinary differential equations are solved by employing suitable similarity variables. The resulting nonlinear system is solved by the spectral quasi‐linearization method. The effects of different nondimensional parameters on various profiles are shown graphically and explored in detail. It is found that the micropolar ferrofluid exhibits a higher energy distribution than that of a classical micropolar fluid. Compared to the classical micropolar liquid, local skin‐friction is more significant for the micropolar magnetite ferrofluid. In the presence of Newtonian heating, the thermal behavior of the micropolar nanofluid is remarkably better than that of the classical micropolar fluid.     

MHD stagnation point flow of Casson fluid over a convective stretching sheet considering thermal radiation,slip condition,and viscous dissipation

This study presents the problem of MHD stagnation point flow of Casson fluid over a convective stretching sheet considering thermal radiation, slip condition, and viscous dissipation. The partial differential equations with the corresponding boundary conditions that govern the fluid flow are reduced to a system of highly nonlinear ordinary differential equations using scaling group transformations. The fourth-order method along shooting technique is applied to solve this system of boundary value problems numerically. The effects of flow parameters on the velocity, temperature, and concentration profiles are presented via graphs. The impact of the physical parameters on the skin friction coefficient reduced Nusselt numbers and reduced Sherwood numbers are investigated through tables. Comparison of the present findings with the previously published results in the literature shows an excellent agreement. It is also noted that a rise in the Eckert number results in a drop in the temperature of the fluid in the thermal boundary layer region of the fluid flow.     

长沙市某办公建筑室内热环境与供暖行为研究

为了研究室内热环境与人员的供暖行为,以长沙市某办公建筑为例,对该办公建筑室内外热湿环境与供暖系统能耗进行了连续监测。根据室内温度、相对湿度与供暖设备能耗数据,分析了室内人员供暖行为以及室内热环境频率特性,并采用逻辑回归方法构建室内供暖设备开启率预测模型。结果表明：该办公建筑冬季室内平均温度为20.1 ℃,平均相对湿度为43.6%;室内供暖设备开启时刻室内温度均值为13.6 ℃,关闭时刻室内温度为22.8 ℃（人员热偏好行为作用下）;根据所构建的室内供暖设备开启率预测模型（sig = 0.000）,得出当室外温度为10.7 ℃时,室内供暖设备开启概率为80%。