Showing papers on "Streamlines, streaklines, and pathlines published in 2021"

Optimization of hybrid nanoparticles with mixture fluid flow in an octagonal porous medium by effect of radiation and magnetic field

Abstract: Investigation of fluid behavior in a cavity enclosure has been a significant issue from the past in the field of fluid mechanics. In the present study, hydrothermal evaluation of hybrid nanofluid with a water–ethylene glycol (50–50%) as the base fluid which contains MoS2–TiO2 hybrid nanoparticles, in an octagon with an elliptical cavity in the middle of it, has been performed. In this problem, the effects of the radiation parameter, porosity, and the magnetic parameter have been analyzed on temperature distribution and fluid flow streamlines and also, on the local and average Nusselt numbers. The governing equations have been solved by the finite element method (FEM). As a novelty, the Taguchi method has been utilized for test design. Further, the response surface method (RSM) has been applied to achieving the optimum value of the involved parameters. The obtained results illustrate that with an augment in the Rayleigh number from 10 to 100, the average Nusselt number will improve by about 61.82%. Additionally, regarding the correlation, it is indeed transparent that the Rayleigh number has the most colossal contribution comparing other factors on the achieved equation, by about 61.88%.

On the hydrothermal features of radiative Fe3O4–graphene hybrid nanofluid flow over a slippery bended surface with heat source/sink

Abstract: The present investigation concentrates on the hydrothermal features of both hybrid nanofluid and usual nanofluid flow over a slippery permeable bent structure. The surface has also been considered to be coiled inside the circular section of radius R. Ferrous and graphene nanoparticles along with the host fluid water are taken to simulate the flow. The existence of heat sink/source and thermal radiation are incorporated within the system. Resulting equations are translated into its non-dimensional form using similarity renovation and solved by the RK-4 method. The consequence of pertinent factors on the flow profile is explored through graphs and tables. Streamlines and isotherms for both hybrid nanofluid and usual nanofluid are depicted to show the hydrothermal variations. The result communicates that temperature is reduced for curvature factor, whereas velocity is found to be accelerated. Heat transfer is intensified for thermal Biot number, and the rate of increment is higher for hybrid nanosuspension. Velocity and temperature are intensified for enhanced nanoparticle concentration. The heat transport process is decreased for the heat source parameter, but the reduction rate is comparatively slower for hybrid nanofluid.

Magneto-hydrodynamic thermal convection of Cu–Al 2 O 3 /water hybrid nanofluid saturated with porous media subjected to half-sinusoidal nonuniform heating

Abstract: The present work aims to examine the thermal efficacy of half-sinusoidal nonuniform heating at different spatial frequencies for a porous natural convection system using Cu–Al2O3/water hybrid nanofluid and magnetic field. The system is presented utilizing a classical square enclosure heated nonuniformly at the bottom wall, and the sidewalls are allowed to exchange heat with the surroundings. The Brinkman–Forchheimer–Darcy model is adopted catering other additional terms for buoyant force and magnetic field. The governing equations are transformed into nondimensional forms and then solved numerically using a finite volume-based computing code. The importance and fundamental flow physics are explored in terms of the pertinent parameters such as the amplitude (I) and spatial frequency (f) of half-sinusoidal heating, Darcy–Rayleigh number (Ram), volume fraction of hybrid nanoparticles ( $$ \phi $$ ), and Hartmann number (Ha). The flow structure and heat transfer characteristics are analyzed and presented utilizing heatlines, streamlines and isotherms and average Nusselt number. The results show that the use of half-sinusoidal nonuniform heating along with hybrid nanofluid can be a viable method for enhancement and control of the overall thermal performance. The study indicates that half-sinusoidal heating could be a promising technique for better heat transfer even in the presence of flow dampening effects like porous media and magnetic fields.

Thermal transport of radiative Williamson fluid over stretchable curved surface

Abstract: The study of incompressible steady Williamson fluid flow is conducted in a curvilinear coordinate system. The flow is bounded below through curves stretchable sheet. Linear thermal radiation effects are considered to observe the heat flow in the system. The model was designed as an application to solar energy in thermal engineering processes. Employing suitable similarity transformations, a set of partial differential equations obtained from the flow situations are converted into a system of non-linear coupled ordinary differential equations. The subsequent equations are elucidated numerically via Runge-Kutta-4 along with the shooting algorithm. The outcomes for different flow properties are displayed and discussed both graphically and numerically. The observations shows that the curvature parameter reduces both velocity and temperature. Radiation parameter boosts the temperature of the fluid but reduces the local Nusselt number. Williamson fluid parameter has a reverse impact on velocity field but it works as a provoking agent for the case of thermal profile. The visual effects in the form of streamlines and isotherms are also presented for different Reynolds number.

Non-Newtonian fluid flow around a Y-shaped fin embedded in a square cavity

Abstract: This study investigates the free convection of Casson fluid inside a square cavity with intruded Y-shaped fin at the bottom surface. The Casson fluid is a non-Newtonian fluid and has an infinite viscosity at zero rates of shear. This is the first time that this fluid is used in the square cavity containing Y-shaped fin at the bottom surface. The Y-shaped fin helps in understanding the constructal theory and enhancing the heat transfer rate from the fin. The main objective of using this fin is to increase the convective heat transfer surface area. The sidewalls of the cavity are kept at cold temperature, the bottom surface at a hot temperature, and the top surface as adiabatic. The tips of the Y-shaped fin are considered as hot, cold, and adiabatic. The effects of the magnetic field and radiation are included in the momentum and energy equations. The influence of viscous heating is neglected. The buoyancy term is included in the momentum equation using Boussinesq approximation. The dimensionless governing equations are solved numerically using a Galerkin weighted residual technique of the finite element method. The effects of Rayleigh number (Ra = 104–106), radiation parameter (Rd = 0–103), Hartmann number (Ha = 0–103), and Casson parameter (γ = 0.1–1) on streamlines, isotherms, dimensionless velocity components, temperature, and local Nusselt numbers along the fin and the bottom heated wall are investigated and presented graphically. It is demonstrated that, in the presence of Y-shaped fin, all the pertinent parameters and dimensionless numbers help in enhancing the heat transfer rate along the bottom surface.

Numerical study of electroosmosis-induced alterations in peristaltic pumping of couple stress hybrid nanofluids through microchannel

Abstract: This paper presents a computational modeling approach to analyze the peristaltic pumping of couple stress hybrid nanofluids regulated by the electroosmosis mechanism through a microchannel. The effects of applied magnetic field, Joule heating and buoyancy have also been computed. In this analytical model, water-based titanium dioxide (TiO2) and silver (Ag) hybrid nanofluids have been considered. For more relevant physical problem, the axial velocity slip and thermal slip conditions have also been introduced. The nonlinear differential equations are simplified by considering the Huckel–Debye approximations as well as lubrication theory, and then the equations have been solved numerically by Mathematica 10 software via the NDsolve commands. The pertinent influences of key parameters on the axial velocity, nanoparticle temperature, Nusselt number and streamlines in the microchannel have been visualized graphically. It is observed that an increase in the thermal Grashof number produces a maximum axial velocity, and temperature of nanoparticles for both water–titanium dioxide and water–silver nanofluids. The maximum axial velocity and nanoparticle temperature occur in water–titanium dioxide as compared with water–silver. The outcomes of this model shall be very useful in the designs of smart electro-peristaltic pumps for thermal systems and drug delivery systems.

Finite element analysis on transient MHD 3D rotating flow of Maxwell and tangent hyperbolic nanofluid past a bidirectional stretching sheet with Cattaneo Christov heat flux model

Abstract: The finite element analysis on the transient magnetohydrodynamic three-dimensional rotating flow of Maxwell and tangent hyperbolic nanofluid flow past a bidirectional stretching sheet with Cattaneo Christov heat flux model has been explored numerically. The thermophoresis and Brownian motion effects are taken into account in the flow governing boundary layer equations. Appropriate similarity transformations are applied for the principal PDEs to transform into nonlinear ODEs. A widely recognized Numerical scheme known as the Finite Element Method is employed to solve the resultant convective boundary layer balances. The portrayal of certain physical parameters on the flow model is portrayed via figures and numerical tables. The temperature and concentration distribution for tangent hyperbolic nanofluid is prominently than that of Maxwell nanofluid, but inverse trend is observed for velocities profiles. An outstanding comparison with existing literature ensures a remarkable accuracy and concludes the rate of convergence is extraordinary for nonlinear differential systems. These examinations are relevant to the field of plastic films, crystal growing, paper production, and cooling of metal sheets.

Interaction of fusion temperature on the magnetic free convection of nano-encapsulated phase change materials within two rectangular fins-equipped porous enclosure

Abstract: The present study encountered the impact of non-dimensional fusion temperature on the free convection of conducting nanofluid within a porous enclosure filled with nano-encapsulated phase change materials (NEPCMs). The enclosure is equipped with two parallel fins that have ability to move in both directions such as vertically as well as horizontally. In particular the particles are structured as core-shell with phase change materials. The phase change of the materials is obtained from the solid to liquid and absorbs the surrounding temperature in the hot region and releases in the cold region. The governing transformed equations are tackled by using the Finite Element Method (FEM). The numerical simulation of the isotherms, streamlines and heat transfer coefficient ratio along with velocity distribution for various parameters are presented. These are affecting a key role on the average and local Nusselt number as well as on the local Bejan number. However, the measure outcomes are; both the longitudinal and transverse velocity profiles boost up with an augmented Rayleigh number; however, the weaker flow field is generated for the increasing Hartmann number.

Free convection and second law scrutiny of NEPCM suspension inside a wavy-baffle-equipped cylinder under altered Fourier theory

Abstract: Background Free convection and second law scrutiny of nano-encapsulated phase change material (NEPCM) suspension along with entropy production inside a circular cold cylinder involving a wavy hot baffle is a significant thermal management aspect subject to various industrial applications. Phase change material (PCM) undergoes a solid-liquid phase mutation at a particular fusion temperature, and absorbs/releases an appreciable amount of energy because of the latent heat of phase mutation. Hence, NEPCMs would be prospective owing to their capability to enhance the working liquids’ performance, keeping the system at a particular cooling temperature. Methods In order to simulatethe free convection along with entropy generation of NEPCMs inside a circular cold cylinder entails a wavy hot baffle under CattaneoChristov heat flux model(Altered Fourier theory) and magnetic field, the finite element method (FEM) could be utilized to solve the governing equations. In this study, the amplitude of baffle could be changeable while its undulation number is fixed at 2. Findings Amplifying Raylegh number intensifies streamlines, isotherms, horizontal and vertical velocities, total entropy generation whittles down local Bejan number. Higher magnetic field strength is responsible for slow movement of NEPCMs and augments local Bejan number. Growth of baffle size yields squeezes the streamlines, horizontal and vertical velocities and intensified tilted isotherms.

Effect of multibanded magnetic field on convective heat transport in linearly heated porous systems filled with hybrid nanofluid

Abstract: The paper attempts to enhance the control of convective transport phenomena in magnetothermal devices applying a technique of multibanded magnetic field. For this demonstration, a typical cavity-like thermal system is considered involving linear heating, porous substance, hybrid nanofluid, and magnetic field. Four identical bands of magnetic fields are applied horizontally with uniform inactive zones between the bands. The transport equations of the coupled multiphysics evolving from the thermal buoyancy (due to linear heating at one sidewall and isothermal cooling at the opposite sidewall), filled porous medium, spatially intermittently active magnetic fields, and the engineered working fluid of Cu–Al2O3/water hybrid nanofluid are solved by an indigenously developed computing code. The study is conducted using the pertinent dimensionless parameters for the following ranges: Darcy–Rayleigh number (Ram = 1–104), Darcy number (Da = 10−5 − 10−1), Hartmann number (Ha = 0–70), and concentration of hybrid nanoparticles ϕ (= 0–2%). The convective phenomena are analyzed using the heatlines (for heat transport), streamlines (flow pattern), isotherms (static temperature), and the average Nusselt number (for heat transfer). The outcomes of this technique of multibanded magnetic field are rigorously compared with other established application methods of magnetic fields. It establishes different local behaviors along with an improved heat transfer. Heatline visualization reveals the definite portraits of heat flow paths depending upon parametric values. Furthermore, the presence of linear heating is in particular treated to explore the insight of linear heating (that featuring multiple heating and cooling zones along with the linear heater), utilizing the local Nusselt number and heatlines. One of the important advantages of this new technique is it is more energy-efficient particularly for the square or shallow cavity. The multibanded magnetic field shows a promising technique for the control of convective transport phenomena involving coupled multiphysics used during sophisticated applications (such as materials processing, biomedical applications, etc.).

Impacts of lorentz force and chemical reaction on peristaltic transport of Jeffrey fluid in a penetrable channel with injection/suction at walls

Abstract: This article aims to inspect the impacts of the chemical reaction and magnetohydrodynamic on the peristaltic transport of a non-Newtonian Jeffrey fluid through a porous channel. The impacts of slip and convective conditions are also considered. The exact outcomes of the mathematical model are computed assuming low Reynolds number Re → 0 and long wavelength δ 1 deliberations. This model is beneficial in physiological systems to empathize with the two-fluid flow behaviors. The involvement of sundry parameters occurred in the flow system is inspected through graphical demonstrations. The trapping phenomena have also been emphasized through drawing streamlines. Outcomes indicate that the velocity declines with raising the magnetic and slip parameters whereas the pumping rate enhances with enlarging λ 1 in the co-pumping region (negative pressure rise) however it displays declining behavior in the free pumping region (positive pressure rise). The current inquiry is also designated for Newtonian fluid λ 1 → 0 as a special case of our analysis. Further, a comparative analysis is also presented for JF with Newtonian fluid.

Natural convection heat transfer and entropy generation in a porous rhombic enclosure: influence of non-uniform heating

Abstract: In this paper, we present a numerical investigation of natural convection heat transfer and entropy generation for a rhombic enclosure with inclination angle, ϕ = 30°, filled with a porous medium. The left and right surface walls of the enclosure are confined to cold temperature bath while we impart non-uniform, varying temperature distribution with unequal phase angles along the top and bottom wall. The flow inside the enclosure is steady, two-dimensional, incompressible and laminar, and the working fluid is air (Pr = 0.71). Numerical experiments have been performed using finite element method-based software COMSOL Multiphysics 5a for Darcy number and Rayleigh number in the extent of 10−4–10−2 and 103–106, respectively, in addition to phase deviation angles varying in the range from 0 to π. The amplitude parameter associated with the temperature delineation of the bottom and top walls is kept constant. The realizations from the numerical investigation are exhibited by streamlines and isotherms, local and average heat transfer Nusselt number along with the local distribution of heat transfer and fluid friction irreversibilities. The rate of heat transfer demonstrates non-monotonic trends and can be considerably influenced by the interplay of the phase shift angle, Rayleigh number and Darcy number. Upon increasing the value of phase shift angle from 0 to π, average Nusselt number initially decreases and thereafter shows an increase in its value. As the Darcy number increases, average Nusselt number for the bottom wall increases, while for the top wall it strongly depends on phase shift angle. In terms of entropy generation, it is found that the significant contributor to irreversibility is induced by heat transfer and the location of maximum entropy varies with the change in phase angle. More specifically, minimum entropy generation for any value of Rayleigh number and Darcy number is obtained for a phase shift angle of π/4 and maximum for 3π/4. The concomitant transport characteristics bear significance from the context of design of thermal systems pertaining to the theme of non-uniform heating with the phase angle being a crucial design parameter.

Galerkin finite element analysis of magneto two-phase nanofluid flowing in double wavy enclosure comprehending an adiabatic rotating cylinder.

Abstract: In this work, the finite element method is employed to simulate heat transfer and irreversibilities in a mixed convection two-phase flow through a wavy enclosure filled with water-alumina nanoliquid and contains a rotating solid cylinder in the presence of a uniform magnetic field. Impact of the variations of undulations number (0 ≤ N ≤ 5), Ra (103 ≤ Ra ≤ 106), Ha (0 ≤ Ha ≤ 100), and angular rotational velocity (- 500 ≤ Ω ≤ 500) were presented. Isotherms distribution, streamlines and isentropic lines are displayed. The governing equations are verified by using the Galerkin Finite Element Method (GFEM). The Nusselt numbers are calculated and displayed graphically for several parametric studies. The computational calculations were carried out using Buongiorno's non-homogeneous model. To illustrate the studied problem, a thorough discussion of the findings was conducted. The results show the enhacement of the maximum value of the flow function and the heat transfer process by increasing the value of Rayleigh number. Furthermore the irreversibility is primarily governed by the heat transfer component and the increment of the waviness of the active surfaces or the cylinder rotational velocity or hartmann number will suppress the fluid motion and hinders the heat transfer process.

Application of rotating circular obstacles in improving ferrofluid heat transfer in an enclosure saturated with porous medium subjected to a magnetic field

Abstract: In this paper, the evaluation of the heat transfer rate and fluid flow in an enclosure with rotating circular obstacles has been studied. The enclosure is filled with a porous medium and subjected to the magnetic field. Fe3O4/water nanofluid has been used to simulate the effect of magnetism. The finite volume method has been applied to solve the equations. To velocity–pressure coupling, the SIMPLE algorithm has been applied. The influence of magnetism on the enclosure in the conductive and non-conductive boundaries along the magnetic field has been investigated. The streamlines and isotherm-lines contours in the conductive and non-conductive boundaries along the magnetic field, the dimensionless angular velocities of the circular obstacles, and their direction have been obtained. The results show that the different temperature cases of the circular obstacles and their direction play an essential role in the flow and heat transfer. The highest and lowest heat transfer rates occur in cold circular obstacles and hot circular obstacles, respectively. Also, the composition of the porous medium and the magnetic field show different behaviors at the heat transfer rate.

MHD darcy-forchheimer nanofluid flow and entropy optimization in an odd-shaped enclosure filled with a (MWCNT-Fe3O4/water) using galerkin finite element analysis.

Abstract: MHD nanoliquid convective flow in an odd-shaped cavity filled with a multi-walled carbon nanotube-iron (II, III) oxide (MWCNT-Fe3O4) hybrid nanofluid is reported. The side walls are adiabatic, and the internal and external borders of the cavity are isothermally kept at high and low temperatures of Th and Tc, respectively. The governing equations obtained with the Boussinesq approximation are solved using Galerkin Finite Element Method (GFEM). Impact of Darcy number (Da), Hartmann number (Ha), Rayleigh number (Ra), solid volume fraction (ϕ), and Heated-wall length effect are presented. Outputs are illustrated in forms of streamlines, isotherms, and Nusselt number. The impact of multiple parameters namely Rayleigh number, Darcy number, on entropy generation rate was analyzed and discussed in post-processing under laminar and turbulent flow regimes.

Numerical simulation of periodic MHD casson nanofluid flow through porous stretching sheet

Abstract: The perspective of this paper is to characterize a Casson type of Non-Newtonian fluid flow through heat as well as mass conduction towards a stretching surface with thermophoresis and radiation absorption impacts in association with periodic hydromagnetic effect. Here heat absorption is also integrated with the heat absorbing parameter. A time dependent fundamental set of equations, i.e. momentum, energy and concentration have been established to discuss the fluid flow system. Explicit finite difference technique is occupied here by executing a procedure in Compaq Visual Fortran 6.6a to elucidate the mathematical model of liquid flow. The stability and convergence inspection has been accomplished. It has observed that the present work converged at, Pr ≥ 0.447 indicates the value of Prandtl number and Le ≥ 0.163 indicates the value of Lewis number. Impact of useful physical parameters has been illustrated graphically on various flow fields. It has inspected that the periodic magnetic field has helped to increase the interaction of the nanoparticles in the velocity field significantly. The field has been depicted in a vibrating form which is also done newly in this work. Subsequently, the Lorentz force has also represented a great impact in the updated visualization (streamlines and isotherms) of the flow field. The respective fields appeared with more wave for the larger values of magnetic parameter. These results help to visualize a theoretical idea of the effect of modern electromagnetic induction use in industry instead of traditional energy sources. Moreover, it has a great application in lung and prostate cancer therapy.