Effect Of Variable Magnetic Field Research Articles

Effects of variable magnetic field and partial slips on the dynamics of Sutterby nanofluid due to biaxially exponential and nonlinear stretchable sheets

Based on both the characteristics of shear thinning and shear thickening fluids, the Sutterby fluid has various applications in engineering and industrial fields. Due to the dual nature of the Sutterby fluid, the motive of the current study is to scrutinize the variable physical effects on the Sutterby nanofluid flow subject to shear thickening and shear thinning behavior over biaxially stretchable exponential and nonlinear sheets. The steady flow mechanism with the variable magnetic field, partial slip effects, and variable heat source/sink is examined over both stretchable sheets. The analysis of mass and heat transfer is carried out with the mutual impacts of thermophoresis and Brownian motion through the Buongiorno model. Suitable transformations for both exponential and nonlinear sheets are implemented on the problem's constitutive equations. As a result, the nonlinear setup of ordinary differential equations is acquired which is further numerically analyzed through the bvp4c technique in MATLAB. The graphical explanation of temperature, velocity, and concentration distributions exhibits that the exponential sheet provides more significant results as compared to the nonlinear sheet. Further, this study revealed that for the shear thickening behavior of Sutterby nanofluid, the increasing values of Deborah number increase the axial velocity.

Effects of variable magnetic field assisted EDM on MRR and surface integrity of AZ80 magnesium

ABSTRACT Magnetic field-assisted electrical discharge machining (MFEDM) is [non-conventional method] employed to optimize and improve output parameters in electrical discharge machining (EDM) and has recently been of great interest to researchers. In EDM, a magnetic field is created by the movement of electrons in the plasma channel. It can be inferred from this theory that a rise in the magnetic field strength raises the plasma channel density and energy concentration. The present study aims to explore the effects of a variable magnetic field on the material removal rate (MRR) and surface integrity in MFEDM, comparing the variable magnetic field-assisted EDM to constant magnetic field-assisted EDM and conventional EDM. The AZ80 magnesium alloy was used for the workpiece which, due to its unique properties, has been widely used in many industries in recent years. Moreover, magnesium is paramagnetic and can yield different results in MFEDM. It was found that the external magnetic field increased the MRR by 58% and reduced the surface roughness in magnesium AZ80. In addition, the variable magnetic field outperformed the constant one in improving MRR and surface roughness. Also, the results showed that the auxiliary magnetic field is more effective on the surface roughness of ferromagnetic metals than paramagnetic metals.

Entropy optimization in hybrid radiative nanofluid flow with effect of variable magnetic field over exponential stretching plate

Researchers have recently become interested in hybrid nanofluids, which are generated by dissipating two solid components in a regular fluid and can increase thermal properties. In this article, entropy optimization of three-dimensional hybrid nanoparticles flow through a bidirectional exponential stretching/shrinking plate is investigated, also MHD and thermal radiation are considered. Through appropriate similarity transformations, the conservative equation of momentum and energy are altered into nonlinear ODEs. A bvp4c method via Matlab software is utilized to solve these equations. The entropy formation is calculated using the solutions of the flow constraints on temperature and velocity. The influence of numerous constraints for instance suction/injection, stretching/shrinking, magnetic parameter, thermal radiation, Prandtl number, temperature exponent parameter, and temperature ratio parameter on flow, temperature, and entropy formation have been deliberated in detail via graphical presentation. The skin friction and local Nusselt number for altered estimations of the physical constraints are also established for practical purposes. The figures show that the stretching/shrinking and magnetic parameter raises the entropy formation while declined the Bejan number.

The Effect of Variable Magnetic Field on Viscous Fluid between 3-D Rotatory Vertical Squeezing Plates: A Computational Investigation

In this paper, the 3-D squeezing flow of viscous incompressible fluid between two parallel plates rotating at the same rate is investigated. The flow is observed under the influence of the varying magnetic field. The flow phenomena are modeled by utilizing the basic governing equations, i.e., equation of continuity, coupled Navier Stokes, and Magnetic Field equations. Using appropriate similarity transformations, the resultant partial differential equations are then transformed into a system of ordinary differential equations. The computational technique is developed via the Homotopy Analysis Method (HAM) to obtain the solution of transformed systems of ordinary differential equations. The influence of several engineering fluid parameters, such as squeeze Reynolds number, magnetic field strength parameter, and magnetic Reynolds number, on velocity and magnetic field components, are observed from different graphs. It has been investigated that by increasing the squeeze Reynolds number, fluid velocity in the y and z directions will be increased as well. On the magnetic field component along the y-axis, an increasing influence of squeezing Reynolds number is also noticed. Similarly, raising the magnetic Reynolds number increases the velocity along the y-axis, whereas the inverse relationship is found for magnetic field components. Furthermore, for each flow phenomenon, an error analysis is also presented.

Effects of variable magnetic field on particle fouling properties of magnetic nanofluids in a novel thermal exchanger system

Magnetic nanofluids, as a new type of heat transfer media, propose a possible way to achieve low energy consumption and carbon neutrality, which has attracted a lot of attention in the heat transfer field. To comprehensively discuss the feasibility of magnetic nanofluids application in heat exchange systems, this paper conducted an experimental study of the particle fouling properties based on Fe3O4–H2O-AG magnetic nanofluids. The effects of variables including Reynolds number, magnetic field form, and magnetic flux density B on the fouling properties were analyzed. The anti-fouling rate η was introduced to evaluate the anti-fouling properties. The results showed that high Reynolds number (Rf (Re = 9000) = 2.83 × 10−6 m2 W K−1), constant parallel magnetic field with high magnetic flux density (Rf (B = 18mT) = 3.86 × 10−6 m2 W K−1), and corrugated tube with twisted turbulator (Rf (with turbulator) = 3.74 × 10−6 m2 W K−1) demonstrated less fouling thermal resistance Rf. Meanwhile, constant parallel magnetic field with high magnetic flux density also exhibited better anti-fouling properties (η(B = 18mT) = 1.35), which indicated that the parallel magnetic field has a positive effect on preventing the deposition of magnetic nanoparticles.

Energy transport analysis in flow of Carreau nanofluid inspired by variable thermal conductivity and zero mass flux conditions

The presence of nanometric particles in the base fluids lead to form nanofluids. Nanofluids are prominent due to their astonishing features in thermally conducting flows and in the development of electronic and mechanical devices. Based on these motivations, we have designed our article to investigate the thermal conduction features in the free and forced convection flow of unsteady Carreau nanofluid due to stretching cylinder with the effects of variable magnetic field. Moreover, the transport of thermal energy in the flow is properly examined by including the impacts of variable thermal conductivity and nonuniform heat rise/fall. Furthermore, the transport of solutal energy in the flow of nanofluid is encountered under the influences of activation energy and binary chemical reactions. A momentous feature of this study is to employ the zero-mass flux condition at the wall of the cylinder. A section of this study is proposed for mathematical modelling of the current problem. Moreover, the impacts of involved physical constraints are explored by employing an efficient numerical technique namely bvp4c. The features of all physical constraints on flow, thermal and solutal curves are illustrated in the form of graphs and discussed with reasonable physical arguments in discussion section of the article. The core findings of this study are mentioned in the section of closing remarks. The core upshot of the current study is that the nanoparticles concentration rate of nanofluid depicts ascending trend for escalating values of activation energy constraint. A significant upsurge in the coefficients of skin friction and Nusselt number is detected with an escalation in the constraints of buoyancy and thermophoresis forces, respectively. The references regarding this article are also provided at the end.

Numerical investigation of an unsteady nanofluid flow with magnetic and suction effects to the moving upper plate

The recent work provides the numerical investigation of an unsteady viscous nanofluid flow between two porous plates under the effect of variable magnetic field and suction/injection. Navier Stokes equations are modeled to study the hydrothermal properties of four different nanoparticles copper [Formula: see text], silver [Formula: see text], aluminum oxide [Formula: see text], and titanium oxide [Formula: see text]. The resultant nonlinear partial differential equations, governing the viscous fluid flow, are solved numerically using Crank–Nicolson scheme. The effect of important physical parameters such as volume fraction, magnetic strength, and porosity parameter are shown both graphically and in tabular form. It is found that due to the greatest thermal diffusivity for nanofluid [Formula: see text], comparatively the velocity increases more rapidly with the increasing value of volume fraction. Due to this effect, it is preferred to use nanofluid [Formula: see text] for transportation purposes.

Heat and Mass Transfer on MHD Jeffrey-Hamel Flow in Presence of Inclined Magnetic Field

In this study, a magnetohydrodynamic Jeffrey-Hamel flow of a viscous, fluid that conducts electricity and is incompressible through a divergent conduit in presence of inclined variable magnetic field with heat and mass transfer has been investigated. The solutions of the governing equations of the MHD flow are obtained numerically since they are non-linear. The numerical scheme used is implemented in a computer software program and the results presented in graphical form. The velocity profile, the temperature profiles, the effect of variable magnetic field and of varying various dimensionless numbers on the flow are analyzed. Jeffrey-Hamel flows are also applied in the diffuser development. Some of the systems include; the channel between the compressor and gas turbine engine burner, the canal at departure from a gas turbine linked to the jet pipe, the canal subsequent to the impellor of a centrifugal compressor, wind tunnels with closed circuits, and water turbine draft tubes among several others. The results provide significant information for the improvement of proficiency and performance of technologies in aerospace, chemical, civil, environmental, industrial and mechanical applications.

Effect of variable magnetic field on the flow between two squeezing plates

In this paper, a viscous fluid is considered between two horizontal and infinite squeezing plates. The unsteady equations of mass and momentum conservation is coupled with the variable magnetic field and energy equations. The governing system of equations along with entropy generation is solved by the Parametric Continuation Method (PCM). A parametric investigation is plotted through graphs for the velocity field and magnetic field components. Also, the entropy generation due to heat transfer, magnetic field and fluid friction is studied through graphs and tables. It is derived that an increase in magnetic Reynolds number, squeezing number or Hartman number increases the fluid temperature. The magnetic field components are also increasing with increase in magnetic flux. It is also derived that an increase in the rate of momentum diffusion increases the entropy generation and Bejan number due to maximum disorderness of molecules near the plates. Applications of the study include automotive magneto-rheological shock absorbers, novel aircraft landing gear systems, heating-up or cooling processes, biological sensor systems and biological prosthetic etc.

Forced Convection of Fe3O4-Water Nanofluid in a Bifurcating Channel under the Effect of Variable Magnetic Field

In this study, forced convection of Fe 3 O 4 –water nanofluid in a bifurcating channel was numerically studied under the influence of variable magnetic. Galerkin residual finite element method was used for numerical simulations. Effects of various values of Reynolds number (between 100 and 500), Hartmann number (between 0 and 3), and solid nanoparticle volume fraction (between 0% and 4%) on the convective heat transfer characteristics were analyzed. It was observed that location and size of the re-circulation zones established in the walls of the bifurcating channel strongly influenced by the variable magnetic field and Reynolds number. Average Nusselt number versus Hartmann number showed different characteristics for hot walls of the vertical and horizontal branching channels. The average Nusselt number enhancements were in the range of 12–15% and 9–12% for hot walls of the branching channel in the absence and presence of magnetic field (at Hartmann number of 3).

3D MHD Free Convective Stretched Flow of a Radiative Nanofluid Inspired by Variable Magnetic Field

This paper carries on investigation to study the effects of variable magnetic field and thermal radiation on free convective flow of an electrically conducting incompressible nanofluid over an exponential stretching sheet. The model implemented in the present study significantly enriches the thermal conductivity and hence more heat transfer capability of nanofluids. The transformed governing equations have been solved numerically using fourth-order Runge–Kutta method along with shooting technique. The influence of variable magnetic field and thermal radiation associated with thermal buoyancy on the dimensionless velocity, temperature, skin friction and Nusselt number have been analyzed. The obtained numerical results in the present study are validated and found to be in excellent agreement with some previous results seen in the literature. The present study contributes to the result that augmented Hartmann number belittles the fluid flow and enhances the fluid temperature and the related thermal boundary layer thickness.

The impact of impinging TiO2 nanoparticles in Prandtl nanofluid along with endoscopic and variable magnetic field effects on peristaltic blood flow

PurposeThe purpose of this paper is to study the variable magnetic field and endoscope effects on peristaltic blood flow of nanofluid containing TiO2 nanoparticles (NPs) through a porous annulus. The Prandtl fluid model is taken into account for the present flow. The mathematical modelling comprises the temperature, continuity, NP concentration, and equations of motion which are further simplified by taking a long peristaltic wave and creeping flow regime.Design/methodology/approachAfter using the long wavelength approximation, the obtained highly non-linear partial differential equations are solved using the homotopy perturbation scheme. The inclusion of the pertinent parameters is discussed mathematically and graphically for the pressure rise, friction forces, temperature profile, and concentration profile. The trapping phenomenon is also investigated with the help of contours.FindingsResults show that the maximum velocity distribution exists near the centre of the annulus, whereas the average time flow boosts the velocity profile. It has also been shown that flow can pass readily without enormous pressure gradient imposed on the endoscope tube unlike the case of the slim section of the problem.Practical implicationsThe nanofluids containing titanium NPs are increasingly utilised since such type of NPs is used by several manufacturers in sunscreen blockers and different types of endoscopy. In endoscopy, the variable magnetic field is used at the tip in order to detect or treat diseases. The NPs are used since they acquire specific thermal properties as compared with base fluids. The present study provides qualitative results showing the effect of inner tube of annulus on the fluid flow, the effect of variable magnetic field, and the change in the temperature profile on the flow field.Originality/valueA new model is introduced that shows the utmost pressure that works against the positive peristaltic pump. It studies the blood flow that results in extremely non-linear partial differential equations that are solved by the homotopy perturbation method. The titanium NPs are being used in blocking the rays that penetrate the epidermis causing skin burns and short ultraviolet ageing rays that cause visible wrinkles, and thus are used in the manufacturing of sunscreens that are partially absorbed through the skin.

Impacts of binary chemical reaction with activation energy on unsteady flow of magneto-Williamson nanofluid

The current review aims to study the combined effects of variable magnetic field and heat generation/absorption on unsteady flow of non-Newtonian Williamson fluid generated by a stretching cylinder in the presence of nanoparticles. An important prospective of this endeavour is to incorporate the impacts of binary chemical reaction and activation energy for revised Buongiorno's model of nanofluid in view of their improved heat transfer. The notion of Boussinesq-approximations is utilized to model the leading equations of momentum, thermal energy and nanoparticle concentration for Williamson fluid. We have employed suitable non-dimensional quantities to alter the leading partial differential equations (PDEs) into a set of ordinary differential equation (ODEs). The numerical simulation is conducted with the help of Runge-Kutta Fehlberg scheme coupled with shooting iteration procedure. The analysis of the obtained results revealed that the assumed physical model is significantly influenced by the key physical parameters, like, magnetic parameter, chemical reaction parameter, activation energy parameter, heat generation/absorption parameter, Brownian motion and thermophoresis parameter. The physical significance of above-mentioned physical parameters on nanofluid velocity, temperature and concentration is argued and exhibited through graphs. The cardinal physical intimation of obtained results is that the nanoparticles concentration enhances with higher activation energy parameter. Further, it is perceived from these results that the rate of heat transfer over the cylinder surface de-escalates with an increase in the reaction rate parameter. It is noted that an augmentation in thermophoresis parameter leads to a rise in nanofluid temperature.

Unsteady mixed convective flow of Williamson nanofluid with heat transfer in the presence of variable thermal conductivity and magnetic field

Latest developments regarding thermo-physical features of flow and heat transfer for non-Newtonian fluids in the presence of nanoparticles have been drawing the attention of many engineers and researchers due to their improved heat transfer features. Amongst several available techniques to reinforce the thermal performance of energy systems, one is the dispersion of solid nanoparticles in base fluids like water. Owing to recent developments in this regard, this communication focuses on time-dependent flow of non-Newtonian Williamson fluid driven by a radially stretching geometry with nanoparticles. The analysis is subject to the effects of variable magnetic field, mixed convection and newly proposed zero nanoparticles mass flux condition. The mathematical formulation is presented with the assistance of basic conservation laws and boundary layer assumptions. The leading transport equations for nanofluid flow have been converted into a system of strongly non-linear ordinary differential equations by employing dimensionless variables. The non-linearity numerical scheme known as Runge-Kutta integration scheme has been implemented to obtain the numerical results for velocity, temperature and concentration fields for numerous set of physical parameters. In this review, impacts of developing parameters on flow field variables are visualized through tables and graphs. The obtained results demonstrate that a higher magnetic field reduces the nanofluids velocity as well as momentum boundary layer thickness. We observe an increment in the rate of heat transfer with Schmidt number. Moreover, it is concluded that an increasing trend is seen in nanofluids temperature with greater thermophoresis parameter. In addition, the numerical results acquired by the applied technique are validated with existing data and excellent correlation is noted.

Heat transfer analysis for peristaltic flow of Carreau-Yasuda fluid through a curved channel with radial magnetic field

Peristalsis of fluids through curved geometries is widely encountered in several industrial and domestic pumping devices. Keeping this fact in mind, effects of variable magnetic field on peristalsis of Carreau-Yasuda (C-Y) fluid through a curved channel with velocity and thermal slip boundary conditions are studied. Heat transfer analysis has been carried out by considering the Joule heating and viscous dissipation effects. The long wavelength and small Reynolds number assumptions are adopted in mathematical modeling of the problem. Resulting non-linear system of differential equations has been solved numerically. Graphical results for axial velocity, temperature, heat transfer rate and stresses at the walls for the different flow parameters are discussed. It is reported that the radially varying magnetic field decreases velocity and increases the temperature of the fluid. Such magnetic field also enhances the heat transfer rate and stresses at the boundaries.

Convective heat transfer of ferrofluid in a lid-driven cavity with a heat-conducting solid backward step under the effect of a variable magnetic field

ABSTRACTThe effect of variable magnetic field on the mixed convective flow of a ferrofluid within a lid-driven cavity has been analyzed numerically. A heat-conducting solid block is located in the bottom part of the cavity. Governing partial differential equations have been formulated taking into account that the magnetic source is a point source located over the moving lid. Analysis has been performed for a wide range of Hartmann number, nanoparticles volume fraction, and magnetic number. It has been found that the growth of the magnetic number leads to the heat transfer enhancement.

MHD 3D free convective flow of nanofluid over an exponentially stretching sheet with chemical reaction

This paper deals with a problem where the effect of variable magnetic field and chemical reaction on free convective flow of an electrically conducting incompressible water based nanofluid over an exponentially stretching sheet has been investigated. In the present study, Buongiorno model associated with Brownian motion and thermophoretic diffusion is employed to describe the heat transfer enhancement of nanofluids. Some suitable similarity transformations reduced the governing boundary layer non-linear partial differential equations into a set of ordinary non-linear differential equations. The transformed equations are then solved numerically using fourth order Runga-Kutta method along with Shooting technique. The major outcomes of the present study is that the magnetic field impedes the fluid motion while thermal as well as mass buoyancy forces accelerate it, the thermophoretic diffusion enhances dimensionless fluid temperature as well as concentration leading to thicker thermal and concentration boundary layers. On the other hand, concentration exponent, Brownian motion parameter and chemical reaction parameter exhibit reverse trend on temperature and concentration. In addition, the presence of magnetic field under the influence of thermal as well as mass buoyancies supports to reduce the rate of heat transfer as well as wall shear stress while the first order chemical reaction develops a thinner concentration boundary layer.

Corrigendum by Simeon Oka, Editor-in-Chief of the Journal Thermal Science requested to replace .pdf file of the paper The effect of variable magnetic field on heat transfer and flow analysis of unsteady squeezing nanofluid flow between parallel plates using Galerkin method by Mohammad Rahimi-Gorji Oveis Pourmehran, Mofid Gorji-Bandpy and Davood Domiri Ganji, Published in the Journal Thermal Science, year 2017,

Due to error of the Editorial staff, unrevised manuscript has been published instead of the REVISED MANUSCRIPT sent by authors after peer review process. The corrected version of this article is printed in this issue on pages pp. 3063-3073<br><br><font color="red"><b> Link to the corrected article <u><a href="http://dx.doi.org/10.2298/TSCI160524180R">10.2298/TSCI160524180R</a></b></u>

The effect of variable magnetic field on heat transfer and flow analysis of unsteady squeezing nanofluid flow between parallel plates using Galerkin method

This paper presents a thermal and flow analysis of an unsteady squeezing nanofluid flow and heat transfer using nanofluid based on Brinkman model in presence of variable magnetic field. Galerkin method is used to solve the non-linear differential equations governing the problem. Squeezing flow between parallel plates is very applicable in the many industries and it means that one or both of the parallel plates have vacillation. The effects of active parameters such as the Hartman number, squeeze number, and heat source parameter are discussed. Results for temperature distribution and velocity profile, Nusselt number, and skin friction coefficient by Galerkin method are presented. As can be seen in results, the values of Nusselt number and skin friction coefficient for CuO is better than Al2O3. Also, according to figures, as nanofluid volume fraction increases, Nusselt number increases and skin friction coefficient decreases, increase in the Hartman number results in an increase in velocity and temperature profiles and an increase in squeeze number can be associated with the decrease in the velocity. <br><br><font color="red"><b> This article has been corrected. Link to the correction <u><a href="http://dx.doi.org/10.2298/TSCI171204246E">10.2298/TSCI171204246E</a><u></b></font>

Study of variable magnetic field and endoscope on peristaltic blood flow of particle-fluid suspension through an annulus

Purpose In this article, the effects of variable magnetic field and endoscope on peristaltic motion of non-Newtonian blood flow of particle-fluid suspension through an annulus have been studied. The non-uniform annulus having incompressible, irrotational and electrically conducting fluid which is filled with rigid particles of different shapes. An assumption of long wavelength and zero Reynolds number approximation is applied to model the governing flow problem. A sinusoidal wave is traveling on the outer tube whereas the inner tube is considered as rigid and moving with a constant velocity.