Magnetic Field Inclination Angle Research Articles

Hydromagnetic flow of two immiscible nanofluids under the combined effects of Ohmic and viscous dissipation between two parallel moving plates

The hydromagnetic flow of immiscible nanofluids between two parallel plates is investigated. Two regions, namely, (i) Region 1 is filled with base fluid kerosene oil with silver Ag nanoparticles, while (ii) Region 2 is filled with base fluid water with titanium dioxide TiO2 nanoparticles. Analytic solutions of nonlinear coupled differential equations have been obtained. The velocity and temperature profile results are discovered to flatten out when the magnetic field's inclination angle decreases. Impact of key parameters like inclination of the magnetic field, Hartmann number and load parameter with thermal conductivity ration have been illustrated graphically.

Effect of the Curvature Angle in a Conduit with an Adiabatic Cylinder over a Backward Facing Step on the Magnetohydrodynamic Behaviour in the Presence of a Nanofluid

A backward facing duct are present in various industrial applications especially those focused on heat transfer. The flow through a curved backward facing duct especially in the presence of nanofluid presents complexities compared to a straight backward facing step (BFS) duct. Therefore, the present numerical study deals a nanofluid flow (Fe3O4-H2O) forced convection in a curved backward facing duct. The objective of this investigation is to visualize at different curvature angles g (0°, 30°, 45°, 60°, 90°) imposed on the top wall of the duct, the effect of Hartmann number Ha (0, 50, 100), magnetic field inclination angle γ (0°, 60°, 90°), Reynolds number Re (10, 100, 200) and nanoparticle volume fraction φ (0 %, 0.05 %, 0.1 %). The dimensionless governing equations are solved using the multigrid finite element method. The results showed that the heat transfer was enhanced at the curved angle g = 90° for large Hartman numbers, thus, the average Nusselt number increased with a ratio of 240.74 % in the case of Hartmann number (Ha = 100).

Thermosolutal Marangoni convection on a permeable flat surface with aligned magnetic field and thermophoretic effect: an OHAM solution

In this venture, the challenge to study the mathematical model and its approximate solution for boundary layer thermosolutal Marangoni convection on a permeable flat surface with thermophoretic velocity and aligned magnetic field has been undertaken. Using a special type of transformation, governing PDEs are converted into ODEs. A semi-analytical method known as optimal homotopy analysis method(OHAM) has been used to develop solutions for proposed mathematical model. The novelty of the study is in the exploration of simultaneous impacts of thermophoretic velocity and inclined magnetic field on flow and heat-mass transport while mass suction/injection is using OHAM. Solutions obtained by OHAM are compared with other published literature and it is revealed that our numerical values are improved by approximately up to 7%. The obtained solutions for various important parameters are displayed in the form of graphs and tables. The study explores the variable behaviors of velocity, temperature, and concentration for growths of Marangoni number, magnetic parameter, and thermophoretic parameter, while there exists mass suction or injection. It reveals that in both cases, i.e. suction and injection cases, velocity grows and temperature and concentration reduce with increasing magnetic parameters and inclination angle of aligned magnetic field and these variations are more prominent in case injection. If the magnetic field is orthogonal to the flat surface, then corresponding Lorentz force produces maximum resistance for the transport phenomenon. The spreading effect of induced surface velocity due to Marangoni convection is observed in the entire boundary layer region in case of mass suction, while for injection case it is witnessed only near the surface. Whereas, for higher value of thermophoretic velocity, the concentration exhibits a reducing trend. For rising values of Marangoni number, wall velocity, Nusselt number, and Sherwood number significantly grow, while magnetic field has contrary impacts.

Magnetic Inclination Evolution of Accreting Neutron Stars in Intermediate/Low-mass X-Ray Binaries

The magnetic inclination angle χ, namely the angle between the spin and magnetic axes of a neutron star, plays a vital role in its observational characteristics. However, there are few systematic investigations of its long-term evolution, especially for accreting NSs in binary systems. Applying the model of Biryukov & Abolmasov and the binary evolution code MESA, we simultaneously simulate the evolution of the accretion rate, spin period, magnetic field, and magnetic inclination angle of accreting NSs in intermediate/low X-ray binaries. We show that the evolution of χ depends not only on the initial parameters of the binary systems, but also on the mass transfer history and the efficiency of pulsar loss. Based on the calculated results we present the characteristic distribution of χ for various types of systems including ultracompact X-ray binaries, binary millisecond pulsars, and ultraluminous X-ray sources, and discuss their possible observational implications.

CuO–Water MHD Mixed Convection Analysis and Entropy Generation Minimization in Double-Lid–Driven U-Shaped Enclosure with Discrete Heating

Abstract The present study explores magnetic nanoliquid mixed convection in a double lid–driven U-shaped enclosure with discrete heating using the lattice Boltzmann method (LBM) numerical method. The nanoliquid thermal conductivity and viscosity are calculated using the Maxwell and Brinkman models respectively. Nanoliquid magnetohydrodynamics (MHD) and mixed convection are analyzed and entropy generation minimisation has been studied. The presented results for isotherms, stream isolines and entropy generation describe the interaction between the various physical phenomena inherent to the problem including the buoyancy, magnetic and shear forces. The operating parameters’ ranges are: Reynolds number (Re: 1–100), Hartman number (Ha: 0–80), magnetic field inclination (γ: 0°– 90°), nanoparticles volume fraction (ϕ: 0–0.04) and inclination angle (α: 0°– 90°). It was found that the N um and the total entropy generation augment by increasing Re, ϕ: and γ. conversely, an opposite effect was obtained by increasing Ha and α. The optimum magnetic field and cavity inclination angles to maximum heat transfer are γ = 90° and α = 0.

Numerical investigation of magneto-thermal-convection impact on phase change phenomenon of Nano-PCM within a hexagonal shaped thermal energy storage

Latent heat storage is among the most effective thermal energy storage techniques. The heat can be stored or released in a phase change substance undergoing melting or solidification. The present research addresses the melting process of paraffin, a phase change material, enhanced with metallic alumina nanoparticles, inside a hexagonal heat storage unit in the presence of a uniform magnetic field is investigated. The melting process occurs during the thermal charge of the latent heat storage unit. The enthalpy-porosity method was employed to model the melting process. The influence of the Lorentz force strength and magnetic field inclination angle as well as the nanoparticle concentration on charging level was scrutinized. It was found that the Lorentz force can suppress the charging level of the thermal energy storage system, while the magnetic field inclination angle can be suitable to control the energy transport performance and melting motion within the thermal energy storage unit. Moreover, raising the nanoadditives concentration diminishes the melting process. Overall, the obtained results confirmed that altering the intensity or direction of the external magnetic field presents indeed a mean for controlling the flow and thermal behavior of nano-enhanced phase change materials. Imposing the Ha up to 500 increases 266% the dimensionless melting time compared to ignoring magnetic field (Ha = 0).

THERMO-FLUIDIC CONVECTIVE FLOW STUDY OF HYBRID NANOFLUID IN AN INVERTED T-SHAPED POROUS ENCLOSURE UNDER UNIFORMLY ACTING MAGNETIC FIELD

This research work attempted to analyze the impact of a magnetic field having various inclination angles on the hydrothermal convective flow and heat transport phenomena in an inverted T-shaped porous enclosure saturated with water-based hybrid nanofluid. Firstly, a comparative study for accessing the significance and applicability of the hybrid nanofluid over simple fluid (water) is accomplished at various Rayleigh numbers. Furthermore, the generalized Darcy-Forchheimer-Brinkmann model having magnetic forces is numerically simulated through the penalty finite element approach. The complete study covers the parametric studies in the presence and absence of magnetic field for parameters, including the broad-ranging values of Hartmann number (Ha), inclination angles of magnetic field (ζ), Rayleigh number (Ra), porosity (∈), and Darcy number (Da). Moreover, results obtained from the parametric studies are graphically demonstrated through the isotherms, streamlines, and the variation of mean Nusselt number plots (Nu<sub>m</sub>). The results variation suggests that the heat transfer rate is getting more robust with Da, Ra, and ∈, though the appearance of the magnetic field restricts the fluid flows and heat transport. Additionally, the increasing angle supports the heat transfer process till ζ = 30 up to some extent, and further, it deteriorates till ζ = 90. Thus, a proper inclination and the magnitude of the magnetic field may be a better choice to control the flow regime and the thermal transport phenomena inside the porous domain.

Study of two-electron temperature plasma sheath using non-extensive electron distribution in presence of an external magnetic field

In this study, the physics of sheath formation in a collisional two-electron temperature plasma in the presence of an oblique external magnetic field has been investigated. At first, a comparative study among the fluid electron model, Boltzmann electron model, and the non-extensive electron model has been carried out and a suitable range of non-extensive parameter q has been predicted. In the latter part, a collisional two-electron temperature plasma is considered. Both the hot and cold electron densities are described using the non-extensive distribution, whereas cold ions are described by the fluid equations. The properties of the sheath are investigated in different collisional regimes by varying the non-extensive parameter (q) and the hot to cold electron densities and temperatures. The magnetic field inclination angle is varied in the limit 1° ≤ α ≤ 5°. It is observed that electron distribution significantly deviates from Boltzmann distribution for nearly parallel magnetic field. Moreover, collision enhanced flux deposition for highly magnetized case is a significant finding of the study. The results obtained in this study can enhance the understanding of plasma–matter interaction processes where multiple electron groups with near parallel magnetic field are found.

Convection analysis of the radiative nanofluid flow through porous media over a stretching surface with inclined magnetic field

Nanofluids flow through porous media constitutes an emerging perspective in many thermodynamic processes and thermal processing optimization. The primary goal of contemporary research from the standpoint of such thermal applications is to examine the nanofluid flow across a vertically placed stretching surface embedded in a porous media. The mathematical formulation of the considered flow is modeled with the consequences of inclined magnetic field and thermal radiations. The Darcy-Forchheimer-Brinkman model addresses the fluid transport within the porous medium. Carbon nanotubes (CNTs) and alumina ceramics are considered nanoparticles and porous media, respectively, and water is regarded as a base fluid in this study. Appropriate transformations have been developed to reduce the governing equations into the dimensionless system. The highly nonlinear transformed system is addressed by using a local non-similarity approach via the bvp4c built-in MATLAB function. The physical implications of the emerging dimensionless parameters on the velocity and thermal profiles of considered nanofluids are studied and discussed in detail. It is perceived that the thermal profile of nanofluid is enhanced with increasing estimations of nanoparticles concentrations and radiation parameters. Furthermore, an increment in Hartmann's number and magnetic field inclination angle diminishes fluid velocity. Furthermore, increasing the Darcy number reduces the temperature distributions of the nanofluids under consideration. Comparing the current study with published articles is also performed to corroborate the reported results. In this regard, an excellent agreement has been achieved. This work is expected to provide important information for the future implementation of innovative heat transfer devices, as well as a valuable reference for researchers studying nanofluids flows under varied assumptions.

Entropy Generation Due to Magneto-Convection of a Hybrid Nanofluid in the Presence of a Wavy Conducting Wall

The two-dimensional, time-independent conjugate natural convection flow and entropy generation are numerically investigated in three different cases of a wavy conducting solid block attached to the left wall of a square cavity. A hybrid nanofluid with titania (TiO2) and copper (Cu) nanoparticles and base fluid water in the fluid part is considered in the presence of a uniform inclined magnetic field. The leftmost wall of the cavity is the hot one and the rightmost one is the cold one. Radial-basis-function-based finite difference (RBF-FD) is performed on an appropriate designed grid distribution. Numerical results in view of streamlines and isotherms, as well as average Nusselt number in an interface and total entropy generation are presented. The related parameters such as Hartmann number, Rayleigh number, conductivity ratio, amplitude in wavy wall, number of waviness, and inclination angle of magnetic field are observed. Convective heat transfer in the fluid part is an increasing function of kr,Ra,γ, while it deflates with the rise in Ha in each case. Total entropy generation increases with the increase in Ra and kr but it decreases with Ha values. Average Bejan number ascends with the rise in Ha and descends with the rise in Ra.

Second Law Analysis of MHD Forced Convective Nanoliquid Flow Through a Two-Dimensional Channel

Abstract The present study deals with fluid flow, heat transfer and entropy generation in a two-dimensional channel filled with Cu–water nanoliquid and containing a hot block. The nanoliquid flow is driven along the channel by a constant velocity and a cold temperature at the inlet, and the partially heated horizontal walls. The aim of this work is to study the influence of the most important parameters such as nanoparticle volume fraction (0%≤ϕ≤4%), nanoparticle diameter (5 nm≤dp≤55 nm), Reynolds number (50≤Re≤200), Hartmann number (0≤Ha≤90), magnetic field inclination angle (0≤γ≤π) and Brownian motion on the hydrodynamic and thermal characteristics and entropy generation. We used the lattice Boltzmann method (LBM: SRT-BGK model) to solve the continuity, momentum and energy equations. The obtained results show that the maximum value of the average Nusselt number is found for case (3) when the hot block is placed between the two hot walls. The minimum value is calculated for case (2) when the hot block is placed between the two insulated walls. The increase in Reynolds and Hartmann numbers enhances the heat transfer and the total entropy generation. In addition, the nanoparticle diameter increase reduces the heat transfer and the irreversibility, the impact of the magnetic field inclination angle on the heat transfer and the total entropy generation is investigated, and the Brownian motion enhances the heat transfer and the total entropy generation.

Gaseous slip flow in a porous two-dimensional rectangular microchannel subjected to inclined magnetic field

In this study, two-dimensional, steady, laminar, and compressible gaseous flow of Newtonian fluid in a rectangular porous microchannel affected by an electromagnetic field, and under local thermal equilibrium condition was analytically investigated in the slip flow region (0.001<Kn < 0.1). The porous microchannel is entirely affected by uniform inclined magnetic field with an angle α from the positive x-axis, the range of this angle is 0 ≤ α ≤ 90°. Also, the porous microchannel effected by uniform electric field which points in the positive z-direction. Thermophysical properties of the fluid were assumed to be constant. The normalized governing equations were asymptotically solved and expressions of the flow velocity components, the pressure, and the temperature were provided using first-order velocity slip and temperature jump boundary conditions. The effects of various parameters on the flow were studied, such as Darcy number, the porosity, the thermal conductivity ratio, the electrical conductivity ratio, Hartmann number, Knudsen number, the electric field to magnetic field ratio (0 ≤ K ≤ 1), and the magnetic field inclination angle. It was found that increasing the permeability of the porous medium increases the flow velocity but decreases its temperature. Further, the results reveal that applying a stronger magnetic field in absence of electric field decreases the flow velocity but increases its temperature. On the other hand, the stronger the electric field, the higher the flow velocity and its temperature. Also, as the magnetic field inclination angle increases the flow velocity decreases. The effects of Darcy number and the electrical conductivity ratio on the heat flux were studied as well. A comparison of the analytical solutions with the numerical results were presented as a validation for this study. The comparison showed that the analytical results were in good agreement with the numerical results.

Radiative thermal analysis for four types of hybrid nanoparticles subject to non-uniform heat source: Keller box numerical approach

The advancement in the thermal engineering presented the idea of nanomaterials with stable thermal consequences and performances. The importance of hybrid nanomaterials attributes importance in solar energy production, electronics devices, heating systems, mechanical processes etc. The hybrid model is classified as a distinct thermal phenomenon with different tiny particles. The thermal evaluation of hybrid nanofluid containing four types of nanoparticles subject to the non-uniform heat source/sink and inclined magnetic field for two-dimensional unsteady flow due to permeable stretched surface has been numerically investigated. Four different types of nanoparticles, copper, titanium dioxide, silver and aluminum oxide have been considered with water base fluid. With the help of similarity transformation, we convert the governing partial differential equation into the ordinary differential equation. To solve these similarity equations a numerical technique known as Keller box method is used. The results are shown graphically and in tabular form. For special cases, comparison of numerical results to the previous results is presented with excellent agreement. The physical onset of parameters due to fluctuated heat transfer rate, wall shear force and Nusselt number is observed. It is observed that change in magnetic field inclination angle declines the velocity profile. The temperature profile can be effectively controlled with interaction of titanium oxide nanoparticles. The presence of heat source enhanced the nanoparticles temperature more effectively.

Three-dimensional magnetic fields of molecular clouds

To investigate the role of magnetic fields in the evolution of the interstellar medium, formation and evolution of molecular clouds, and ultimately the formation of stars, their three-dimensional (3D) magnetic fields must be probed. Observing only one component of magnetic fields (along the line of sight or parallel to the plane of the sky) is insufficient to identify these 3D vectors. In recent years, novel techniques for probing each of these two components and integrating them with additional data (from observations or models), such as Galactic magnetic fields or magnetic field inclination angles, have been developed, in order to infer 3D magnetic fields. We review and discuss these advancements, their applications, and their future direction.

Insight view on the CFD simulation of magneto-hydrodynamics natural convection in wavy enclosure with trapezoidal heater and circular cylinder

The present work examines numerically using a finite element scheme the magnetic field on natural convection within I-shaped wavy-walled enclosure filled by a nanofluid and porous medium. The porous medium had been modeled by the Darcy–Brinkman model while a single phase model treats the nanofluid. The thermal equilibrium model had been applied between the nanofluid and porous medium under steady-state conditions. The enclosure contains a trapezoidal heater attached to its bottom wall with an internal heated circular cylinder immersed in the enclosure. The two wavy walls are kept at a cold temperature, while the rest walls are insulated. The influence of the Rayleigh number , Darcy number , Hartmann number , nanofluid loading , magnetic field inclination angle , trapezoidal heater length , location of the trapezoidal heater , and position of the circular cylinder on fluid flow and heat transfer have been discussed deeply. It is obtained that the Nusselt number increases as the Rayleigh number, Darcy number, magnetic field angle increase, and the Hartmann number decreases. Also, for better heat transfer it is obtained that the center location gives the highest value at . Also, the location of the trapezoidal heater in the right region at reveals the best location in terms of heat transfer improvement.

Proton beam-driven instabilities in an inclined magnetic field

In this paper, the electrostatic and electromagnetic instabilities of a magnetized proton–DT plasma relevant to the fast ignition scheme of inertial fusion were examined. The magnetic field and proton beam define a plane and the magnetic field vector has the orientation angle of θ. The dispersion relation of two-stream and filamentation modes was first derived using the conservation, Euler, and Maxwell equations. Then, the more general case describing the wave propagation in an arbitrary direction in the two-dimensional case was derived symbolically. It is demonstrated that in a magnetized beam–plasma system, the two-stream instability depicts two separated growth curves, one larger than the other and there exists a stable frequency band between them. This zone will grow as the magnetic field inclination angle increases such that the smaller two-stream peak vanishes at the limiting angle of θ→π/2. The splitting in the growth rate curve becomes obvious at magnetic field parameter Ωe>0.5. The pure filamentation instability of the beam–plasma is about two orders of magnitude smaller than the two-stream instability and it just contributes to magnetic field orientation θ=0. In a two-dimensional case, the mixed electrostatic/electromagnetic instabilities contribute to the final growth rate curve producing an X-like shape. The interface point of two growth curves is characterized by coordinate (∼1.0, tan(θ)) in the zx-plane.

Study on the characteristics of non-Maxwellian magnetized sheath in Hall thruster acceleration region

The secondary electron emission (SEE) and inclined magnetic field are typical features at the channel wall of the Hall thruster acceleration region (AR), and the characteristics of the magnetized sheath have a significant effect on the radial potential distribution, ion radial acceleration and wall erosion. In this work, the magnetohydrodynamics model is used to study the characteristics of the magnetized sheath with SEE in the AR of Hall thruster. The electrons are assumed to obey non-extensive distribution, the ions and secondary electrons are magnetized. Based on the Sagdeev potential, the modified Bohm criterion is derived, and the influences of the non-extensive parameter and magnetic field on the AR sheath structure and parameters are discussed. Results show that, with the decrease of the parameter q, the high-energy electron leads to an increase of the potential drop in the sheath, and the sheath thickness expands accordingly, the kinetic energy rises when ions reach the wall, which can aggravate the wall erosion. Increasing the magnetic field inclination angle in the AR of the Hall thruster, the Lorenz force along the direction acting as a resistance decelerating ions becomes larger which can reduce the wall erosion, while the strength of magnetic field in the AR has little effect on Bohm criterion and wall potential. The propellant type also has a certain effect on the values of wall potential, secondary electron number density and sheath thickness.

Numerical analysis of electromagnetic squeezing flow through a parallel porous medium plate with impact of suction/injection

Over the years, the squeezing fluid motion between parallel plates has generated the research interest in many investigators due to its various engineering and industrial applications such as injection modeling, compression and polymer process industry. With these motivations, in the current article, the transient state electro-osmotic squeezing propulsion of viscous liquid between two parallel plates through a porous medium with the impact of radiative heat flux has been examined. The applied magnetic field inclination angle ranges from 0 to 90 degrees and moving closer together causes the plates to squeeze one another orthogonal to the plates’ surfaces. Through the suitable similarity transformations, the nonlinear partial differential equations characterizing the proposed flow model are reduced to a set of nonlinear ordinary differential equations. The numerical findings were achieved via MATLAB software. It is determined that the applied electric and magnetic field have the impact on the velocity and heat transfer of squeezing flows. Increasing the electroosmosis parameter as well as the electric field parameters have a considerable effect on temperature augmentation. The results of the current study can be used in various industrial applications such as chemical engineering, hydraulic lifts, polymer processing and power transmission.

Convective heat transfer in I-shape heat sink under the action of Lorentz force via LBM

Via the non-orthogonal multiple-relaxation time Lattice Boltzmann Method, the natural convection phenomenon inside I-shape heat sink under the effect of Lorentz force is investigated. The cavity is filled with MWCNT-Fe3O4/water hybrid nanofluid, and three cold and three hot tubes exist inside the cavity at the same time. The influences of Rayleigh number (103–106), Hartmann number (0–100), magnetic field tilt angle θ (0 – π/2), and different cold and heat pipe arrangements (Case 1–Case 5) on the heat transfer and fluid flow are numerically simulated. The calculated results are shown by the variation of flow lines, isotherms and the average Nusselt number. The results show that the amplitude of the flow function is always the largest for Case 5, which is the best arrangement from the fluid motion point of view, while Case 2 has the largest Nusselt number for different Rayleigh numbers, magnetic field inclination angle θ and different Hartmann numbers, which is the best arrangement from the heat transfer efficiency point of view. However, with different cold and hot pipe arrangements, the average Nusselt number increases when the Rayleigh number and the magnetic field inclination angle θ increase. In contrast, as Hartmann number increases, the average Nusselt number decreases. The local Nusselt number of the cold and hot tubes is further investigated, comparing the discrepancy of the heat transfer performance near each wall surface.

Double-diffusive convection in a magnetic nanofluid-filled porous medium: Development and application of a nonorthogonal lattice Boltzmann model

In this work, to fill the rare reports on double-diffusive convection (DDC) considering the effects of porous medium, nanofluid, and magnetic field at the same time, we first developed a full nonorthogonal multiple-relaxation-time lattice Boltzmann (LB) model for DDC in a nanofluid-filled porous medium subjected to a magnetic field. The capability of the newly proposed model is then verified. By solving specific problems via the full model with specific control parameters, we show that the nonorthogonal LB model is accurate for handling the effects of the porous medium, nanofluid, and magnetic field. Finally, we apply the model to DDC in an Fe3O4–water nanofluid-filled porous cavity with a hot left boundary and examine the effects of magnetic field intensity and inclination angle on the flow, heat, and mass transfer inside the porous medium. Results show that heat and mass transfer can both be adjusted by varying the intensity and inclination angle of the magnetic field. When the external magnetic field is applied, the heat and mass transfer along the hot wall declines monotonously with increasing the strength of the magnetic field. In contrast, the average Nu and Sh increase at first and then decrease with the inclination angle of the magnetic field, reaching the maximum at around γ = 45°. Results in this work pave a tunable way for heat and mass transfer regulation inside a magnetic nanofluid-fill porous medium. In addition, this work provides essential reference solutions for further study on DDC in a nanofluid-filled porous medium subjected to a magnetic field.