Magnetohydrodynamic Heat Transfer Research Articles

Analysis of unsteady heat and mass transfer in rotating MHD convection flow over a porous vertical plate

The aim of this research paper is to investigate the rotational flow of an unsteady magnetohydrodynamic heat and mass transfer flow due to convection over a vertical porous semi-infinite plate. The plate undergoes continuous circular motion, maintaining a constant velocity. To achieve this, we worked on both numerical methods and analytical techniques, particularly utilizing perturbation methods to solve the governing partial differential equations. Consequently, we derive an expression for the Nusselt and Sherwood numbers. We delve into the analysis of the velocity profile, temperature distribution, and concentration variation, exploring their behaviour under different physical parameters, including the magnetic field parameter, Grashof num-ber, Soret number and Schmidt number, as well as the Prandtl number. Our findings reveal that the velocity increases with rising values of Grashof, modified Grashof and Soret numbers, whereas it decreases with declining values of the magnetic field parameter, Prandtl number and Schmidt number. Additionally, as rotation gradually intensifies, the fluid velocity closely follows the boundary and becomes negligible as it moves away from it. To facilitate a comprehensive examination of the fluid flow and heat and mass transfer characteristics, we employ graphical representations. Furthermore, this paper offers an in-depth discussion of the underlying physical aspects and their implications.

MHD Flow and Heat Transfer of Carreau Fluid with Radiation and Heat Source Effect

This article investigates the effects of radiation and heat transfer in the context of Magnetohydrodynamic (MHD) flow of a Carreau liquid over a non-linearly shrinking sheet, using a numerical approach. To tackle the problem, the governing partial differential equations (PDEs) are appropriately transformed into a set of ordinary differential equations (ODEs). These resulting non-linear ODEs are then solved numerically using the fourth-order Runge-Kutta (R-K) method, accompanied by the shooting technique to ensure accuracy and convergence. The study reveals various significant physical characteristics such as the Prandtl number, Weissenberg number, radiation parameter, heat source, and magnetic parameter, all of which play critical roles in influencing the flow and heat transfer behavior. These characteristics are analyzed and presented graphically, providing a clear understanding of how different physical parameters affect the MHD Carreau liquid flow. The findings offer valuable insights into the dynamics of such systems under varying physical conditions, contributing to the broader understanding of heat and mass transfer in complex fluids.

A 2D numerical study of magnetohydrodynamic heat transfer performance within heat sink package equipped with cylindrical fins improved with helical trapezoidal wings and filled by radiative nanofluid

Cooling electronic devices using heat sinks is one of the main fields in which academics are working to develop them. This manuscript presents a novel numerical study using Comsol Multiphysics to optimize heat sink performance through the strategic integration of magnetohydrodynamic (MHD) radiative nanofluid and innovative helical trapezoidal wings on cylindrical fins. The research advances the field by systematically replacing classical cylindrical fins with those provided with cylindrical wings as a first step, and with trapezoidal shapes as a second step and subsequently introducing helical trapezoidal wings instead of the aligned shape to enhance efficiency. Comsol Multiphysics 3.4 software is used to conduct the study applying finite element method. The 2D heat sink problem is modelled as a square cavity, which is equipped with 2D longitudinal section of cylindrical fins and filled with MHD radiative nanofluid. The study examined the impact of using cylindrical wings attached laterally on the cylindrical fins. Then, the efficiency of cylindrical wings is compared with trapezoidal shape. Finally, the helical trapezoidal wings are used to enhance the heat sink efficiency. The findings reveal substantial performance improvements: with nanofluid by 42.83%, enhancement with radiation by 54.19%, with cylindrical wings by 22.38%, and a superior 10.7% efficiency increase with trapezoidal wings. In addition, using helical trapezoidal wings is the optimum for the heat sink performance by 7.26%. This work is poised to appeal to a broad readership by offering valuable insights into optimizing heat sink configurations for enhanced thermal management.

Magnetohydrodynamic Analysis and Fast Calculation for Fractional Maxwell Fluid with Adjusted Dynamic Viscosity

From the perspective of magnetohydrodynamics (MHD), the heat transfer properties of Maxwell fluids under MHD conditions with modified dynamic viscosity present complex challenges in numerical simulations. In this paper, we develop a time-fractional coupled model to characterize the heat transfer and MHD flow of Maxwell fluid with consideration of the Hall effect and Joule heating effect and incorporating a modified dynamic viscosity. The fractional coupled model is numerically solved based on the L1-algorithm and the spectral collocation method. We introduce a novel approach that integrates advanced algorithms with a fully discrete scheme, focusing particularly on the computational cost. Leveraging this approach, we aim to significantly enhance computational efficiency while ensuring accurate representation of the underlying physics. Through comprehensive numerical experiments, we explain the thermodynamic behavior in the MHD flow process and extensively examine the impact of various critical parameters on both MHD flow and heat transfer. We establish an analytical framework for the MHD flow and heat transfer processes, further investigate the influence of magnetic fields on heat transfer processes, and elucidate the mechanical behavior of fractional Maxwell fluids.

Some remarks on thermo-physical properties of magnetohydrodynamics heat and mass transfer of nano-fluid flow over a nonlinear permeable stretching sheet

Some remarks on thermo-physical properties of magnetohydrodynamics heat and mass transfer of nano-fluid flow over a nonlinear permeable stretching sheet

Significance of nanoparticle aggregation for thermal transport over magnetized sensor surface

Abstract This article explores the dynamics of nanofluids consisting of copper (TiO2) nanoparticles suspended in water, as they interact with sensor surfaces between two parallel squeezing plates with porous characteristics. This research specifically targets applications involving enhanced heat transfer and magnetohydrodynamic (MHD) control in nanofluid systems. The primary aim is to analyze the effects of nanoparticle aggregation and non-aggregation on sensor surfaces, considering MHD formations and heat transfer in the energy and momentum equations. The research adopts a steady-state fluid condition and utilizes similarity transformations to convert partial differential equations into more manageable ordinary differential equations. The methodology involves shooting methods for solving these nonlinear ordinary differential equations and employs graphical analyses to study the impacts of various parameters such as permeability, magnetic influence, squeeze flow, and radiation on the temperature and velocity profiles of the nanofluid. The results reveal significant dependencies of temperature and velocity profiles on the studied parameters, illustrating varied behaviors in scenarios of both aggregation and non-aggregation of nanoparticles. The findings emphasize how each parameter distinctively influences the heat and flow characteristics of the nanofluid, offering insights into optimizing conditions for better performance and control in practical applications. Future research could focus on extending the model to include transient fluid states and exploring the effects of other nanoparticle materials and shapes. There is also potential to investigate the interactions under different environmental conditions and to incorporate more complex boundary conditions to simulate real-world applications more accurately. Further experimental validation of the theoretical predictions would be beneficial to enhance the reliability and applicability of the findings.

A numerical inquiry of the MHD radiative thin film nanofluid flow and heat transfer augmentation for Ni and Ta nanoparticles of different shapes dispersed in C 12 H 26–C 15 H 32 over an unsteady, curved stretching surface

Thin films are a versatile technology used in various industries, including light-emitting diodes, magnetic recording media, electronic device manufacturing, and optical coating. They are crucial for studying quantum phenomena, superlattices, and multiferroic materials. Their small size allows for better thermal transport studies due to the combination of thin film flow and nanoparticles. Therefore, this study aims to investigate thin film flow and heat transfer with the effects of thermal radiations, magnetic field, and velocity slip in association with tantalum ( Ta ) and nickel ( Ni ) nanoparticles that emerged in kerosene oil ( C 12 H 26 − C 15 H 32 ) toward a curved stretching surface. A review of the pertinent literature indicates that no research has previously been done on the present problem of an unsteady thin film flow across a curved stretching surface. The problem under consideration is modeled by choosing the curvilinear coordinate system. The controlling nonlinear system of partial differential equations is transformed into the system of ordinary differential equations by using an appropriate similarity transformation and then solved numerically using the BVP 4 C technique in MATLAB . The impact of significant physical parameters on velocity, temperature, skin friction, and Nusselt numbers are depicted through graphs and radar charts. The investigation highlights the significant influence of magnetohydrodynamics ( MHD ) , thermal radiation, volumetric fraction, and velocity slip on the enhancement of nanofluid temperature. It is also noted that cylindrical-shaped Ta nanoparticles exhibited the maximum velocity, while blade-shaped Ni nanoparticles showed the lowest. Moreover, the maximum and minimum temperatures were observed for blade-shaped Ni nanoparticles and cylindrical Ta nanoparticles, respectively. Additionally, the maximum and minimum values of skin friction are found for cylindrical Ni nanoparticles and blade-shaped Ta nanoparticles, respectively. Similarly, the maximum and minimum Nusselt numbers are recorded for cylindrical Ta nanoparticles and blade-shaped Ni nanoparticles, respectively.

Influence of activation energy and variable thermal conductivity on magneto-convective nonlinear thermo-radiative Casson nanofluid containing motile microorganisms over a sinusoidal surface

The activation energy of convective-radiative nanoliquids with sinusoidal walls has garnered significant academic interest in recent years. This focus arises due to the pivotal applications of nanoparticles in thermal engineering, industrial processes, and medical sciences. This article investigates the magnetohydrodynamic heat transfer characteristics of Casson nanofluids containing microorganisms influenced by an oscillatory surface. The study incorporates temperature-dependent viscosity and utilizes Buongiorno’s mathematical model to account for nonlinear thermal radiation, Brownian motion, and thermophoretic effects from using nanomaterials in Casson fluids. These effects enhance thermal conductivity, improving the heat transportation phenomenon while considering gyrotactic microorganism density distributions. The boundary layer flow problem is formulated using partial differential equations and associated boundary conditions, subsequently numerically simulated using the bvp4c function. The investigation explores the thermal behavior of nanoparticles in the presence of bioconvection phenomena, Lorentz force, chemical reactions, and activation energy. As a result, this model addresses variable thermal conductivity and bioconvection aspects in Casson nanofluids over a sinusoidal surface. Numerically computed results for the Nusselt number, motile density, and Sherwood number provide insights into several essential features. The findings reveal that an increase in the Casson fluid parameter correlates with a decreased velocity profile. The assumptions of variable thermal conductivity and temperature-dependent viscosity prove more effective in raising the temperature of nanoparticles. The nanoparticle concentration profile rises noticeably for smaller Schmidt number Sc values when the activation energy parameter is higher than larger Sc values. Additionally, the presence of microorganisms in Casson nanofluids leads to increased temperatures due to an elevation in the bioconvection Rayleigh number. Moreover, heightened oscillating frequency parameters decrease nanoparticle concentration and microorganism density. Including activation energy and oscillating frequency parameters further enhances the understanding of nanoparticle concentration and microorganism density dynamics, offering valuable contributions to theoretical research and practical applications across multiple interdisciplinary fields.

Suction and double stratification effect on unsteady MHD heat transfer nanofluid flow over a flat surface

The objective of the current work is to examine the influence of suction on the unsteady Magnetohydrodynamic (MHD) thermal and mass transfer of a nanofluid flow past a flat sheet in the occurrence of double stratification. The governed highly non-linear PDEs along with corresponding appropriate boundary circumstances are first converted into dimensionless system by the use of similarity translations. The numerical methodology used for solving the transformed ordinary differential equations (ODEs) is often known as the Keller box procedure. This study investigates and visually represents the impact of non-dimensional factors such as Hartman number, Prandtl number, Suction, Eckert number, unsteadiness factor, thermal and solutal stratification on the distributions of velocity, concentration, temperature, drag force, Nusselt, and Sherwood number. The numerical calculation and graphical presentation are conducted to evaluate the impacts of several significant quantities on the flow model. It has been discovered that a rise in the suction parameter leads to an enhancement in the velocity gradient, while simultaneously causing a reduction in the concentration and temperature profiles. The outcomes of the study could have implications for various engineering and industrial applications that control and manipulate fluid flows and heat transfer. The results of the research may have ramifications for a wide range of industrial and engineering applications that control and regulate heat transfer and fluid dynamics.

Dynamics of ternary nanofluid through radiated sensor surface: Numerical investigation

Application: The impact of flow, heat transfer, and magneto hydrodynamics on sensor surfaces between two parallel compressing plates with porous walls has been examined in this study. This study focuses on understanding unsteady compressed flow in two dimensions, utilizing Aluminum oxide, copper oxide, and titanium dioxide with base fluid polymers as the base fluid. Nanofluids, known as nanometer suspensions in traditional nanoscale fluid transfer, are explored for their potential application in improving lubricative and cooling properties. Purpose and methodology: This study aims to investigate the behavior of a tri-hybrid nanofluid (Aluminum oxide, copper oxide, and titanium dioxide with base fluid polymers) in terms of flow dynamics, heat transfer, and magneto hydrodynamics. Energy and momentum equations, considering magneto hydrodynamic forms and heat transfer, are analyzed. The study employs numerical methods, including similarity transforms and a shooting approach, to solve the governing equations. Core findings: Several parameters, including permeable parameter, magnetic parameter, squeeze flow index parameter, volume fraction by nanoparticles, and radiation parameter, are investigated for their effects on temperature profile and velocity profile. The study illustrates these effects graphically and discusses the influence of these parameters on different components of velocity and temperature fields. Additionally, the impact of the radiation parameter ([Formula: see text] on temperature fields is examined for both positive. Future work: Future research may focus on further optimizing the tri-hybrid nanofluid composition for specific applications, exploring additional parameters that may affect flow behavior, heat transfer, and entropy generation. Additionally, experimental validation of the numerical findings and the development of more advanced numerical techniques for solving complex fluid dynamics problems could be the areas of interest for future work.

Linear and nonlinear stretching sheet for enhanced heat and mass transfer in Casson nanofluid with activation energy

In this study, we delve into the magnetohydrodynamic heat and mass transfer flow of a Casson nanofluid over specifically chosen linear and nonlinear stretching surfaces embedded in a porous medium to understand their distinct effects on fluid behavior. By focusing on the influences of Brownian motion, thermophoresis, thermal radiation, and chemical reactions, we transformed nonlinear partial differential equations into ordinary differential equations, leveraging the Runge-Kutta method and Shooting Techniques for numerical solutions of momentum, temperature, and concentration profiles under predetermined boundary conditions. Our results, depicted in both graphical and tabular forms, shed light on how various parameters, including the Casson fluid characteristics, magnetic fields, buoyancy ratio, and mixed convection effects, influence fluid dynamics. A notable finding is that an increase in the Brownian motion parameter intensifies the fluid velocity and temperature profiles, but reduces its concentration profile, unveiling complex interactions within the nanofluid dynamics. This investigation underscores the importance of linear and nonlinear stretching surfaces in mimicking practical industrial scenarios, thereby providing insights that are crucial for optimizing processes such as coating, cooling of electronic devices, and in the manufacturing of thin plastic films, where precise control over heat and mass transfer is essential.

Entropy generation and activation energy on nonlinearly thermo-radiative and magnetohydrodynamic heat transfer of Jeffrey nanofluid with non-uniform heat source/sink using SQLM

ABSTRACT Entropy generation and activation energy analysis on MHD heat and mass transfer of Jeffrey nanofluid under the impact of nonlinear thermal radiation and heat source/sink (non-uniform) over a linearly stretching sheet has been investigated numerically using Spectral Quasilinearization Method (SQLM). The Brownian motion with thermophoretic effects has been utilized. The basic equations concerned with the problem are solved numerically. The impacts of different governing physical parameters are analyzed on the velocity, temperature, and concentration fields, along with entropy generation, and Bejan number profiles are analyzed graphically. It is found that the concentration profiles have a mixed tendency with magnetic parameters. In addition, the temperature profiles increase in the presence of Brownian motion with thermophoresis effects, whereas the composite behavior is noticed on the entropy generation profiles. It is also found that both the temperature and concentration profiles diminish for various values of Deborah number while the velocity profile increases. Also, it is noticed that both the temperature profiles increase for enhanced values of the space-dependent and time-dependent parameters. Due to activation energy, the Bejan number profiles decrease, whereas the entropy generation profiles increase far away from the expandable sheet but decrease closer to the sheet.

Transient magnetohydrodynamic heat and mass transfer analysis of chemically reacting fluid flow over oscillatory permeable media

This study focuses on the numerical observation of the convective motion of chemically active magnetohydrodynamic (MHD) fluid through a vertically oriented permeable medium, incorporating variations in mass and heat transfer. The fluid type is assumed to be incompressible, chemically strongly ionized and viscous with some mass infusibility. The model associated with this problem is solved by a highly stable Implicit Finite Difference Method (IFDM). The method is used for small and large deflection of the physical parameters, which results in a noticeable fluid flow behavior. Numerical configuration is graphically depicted to scrutinize the fluid behavior. The momentum, energy, concentration diffusion, skin friction, Nusselt number and Sherwood number are investigated for numerous factors such as magnetic field, permeability and chemical reaction rate. The current study unveils significant findings, demonstrating that a heightened rate of chemical reaction in the presence of magnetic effects, coupled with specific porosity, diminishes ionization energy, resulting in a concurrent decrease in the concentration and momentum profiles of the fluid flow. The rise in the viscous diffusion rate is attributed to escalating values of the Schmidt number, causing an augmentation in dynamic viscosity and consequently resulting in an overall reduction in the momentum of the fluid flow.

Analyzing the MHD Bioconvective Eyring–Powell Fluid Flow over an Upright Cone/Plate Surface in a Porous Medium with Activation Energy and Viscous Dissipation

In the field of heat and mass transfer applications, non-Newtonian fluids are potentially considered to play a very important role. This study examines the magnetohydrodynamic (MHD) bioconvective Eyring–Powell fluid flow on a permeable cone and plate, considering the viscous dissipation (0.3 ≤ Ec ≤0.7), the uniform heat source/sink (−0.1 ≤ Q0 ≤ 0.1), and the activation energy (−1 ≤ E1 ≤ 1). The primary focus of this study is to examine how MHD and porosity impact heat and mass transfer in a fluid with microorganisms. A similarity transformation (ST) changes the nonlinear partial differential equations (PDEs) into ordinary differential equations (ODEs). The Keller Box (KB) finite difference method solves these equations. Our findings demonstrate that adding MHD (0.5 ≤ M ≤ 0.9) and porosity (0.3 ≤ Γ ≤ 0.7) effects improves microbial diffusion, boosting the rates of mass and heat transfer. Our comparison of our findings to prior studies shows that they are reliable.

Effects of enclosure shape on MHD nanofluid flow and irreversibility in different shaped systems under fluid volume constraint

PurposeThe purpose of this study is to investigate the influence of enclosure shape on magnetohydrodynamic (MHD) nanofluidic flow, heat transfer and irreversibility in square, trapezoidal and triangular thermal systems under fluid volume constraints, with the aim of optimizing thermal behavior in diverse applications.Design/methodology/approachThe study uses numerical simulations based on a finite element-based technique to analyze the effects of the Rayleigh number (Ra), Hartmann number (Ha), magnetic field orientation (γ) and nanoparticle concentration (ζ) on heat transfer characteristics and thermodynamic entropy production.FindingsThe key findings reveal that the geometrical design significantly influences fluid velocity, heat transfer and irreversibility. Trapezoidal thermal systems outperform square systems, while triangular systems achieve optimal enhancement. Nanoparticle concentration enhances heat transfer and flow strength at higher Rayleigh numbers. The magnetic field intensity has a significant impact on fluid flow and heat transport in natural convection, with higher Hartmann numbers resulting in reduced flow strength and heat transfer. The study also highlights the influence of various parameters on thermodynamic entropy production.Research limitations/implicationsFurther research can explore additional geometries, parameters and boundary conditions to expand the understanding of enclosure shape effects on MHD nanofluidic flow and heat transfer. Experimental validation can complement the numerical simulations presented in this study.Originality/valueThis study provides valuable insights into the impact of enclosure shape on heat transfer performance in MHD nanofluid flow systems. The findings contribute to the optimization of thermal behavior in applications such as electronics cooling and energy systems. The comparison of different enclosure shapes and the analysis of thermodynamic entropy production add novelty to the study.

Numerical calculation and fast method for the magnetohydrodynamic flow and heat transfer of fractional Jeffrey fluid on a two-dimensional irregular convex domain

In this paper, we study the magnetohydrodynamic (MHD) flow and heat transfer of the fractional Jeffrey fluid in a straight channel, of which the cross section is a two-dimensional irregular convex domain. We consider a spatial fractional operator to modify the classical Fourier's law of thermal conduction, and obtain the time-space fractional coupled model. The fractional coupled model is solved numerically by the L2−1σ method in the temporal direction and the unstructured mesh finite element method in the spatial direction. Besides, we prove the stability and convergence of the numerical scheme. In order to reduce the computational time, a fast method is proposed. Finally, a numerical example is given to verify the theoretical analysis and the efficiency of the fast method. Furthermore, an example is considered to discuss the effects of the fractional parameters on the MHD flow and heat transfer of the fractional Jeffrey fluid.

Convection heat transfer of MHD fluid flow in the circular cavity with various obstacles: Finite element approach

In the present research, a study has been conducted on a model to investigate magnetohydrodynamic (MHD) heat and mass transfer phenomena. In the geometry of this model, there is a circular cavity with a variable number of obstacles in each step. At each stage, some obstacles are heated, and its effect on fluid flow and heat transfer is investigated. Solving and developing partial differential equations is done using the finite element method. The effects of Rayleigh and Hartmann numbers on flow lines, isotherms, and equivalent concentrations have been investigated, and the output was displayed as contours and graphs. Finally, the Nusselt diagram is displayed. The main purpose of the present study is to evaluate the effect of changes in Rayleigh and Hartmann numbers in different geometries on its behavior. This particular flow configuration was chosen because of the fundamental role of magnetohydrodynamics and its widespread use in engineering, industry, and medicine. The findings of this research show that in almost all investigated geometries, the behavior of streamlines, isotherms, and isothermal concentrations is anti-symmetrical at X = 0.5. Also, with the heating of the upper obstacles, the total Nusselt number decreases, and with the heating of the lower obstacles, the total Nusselt number increases. The behavior of the total Nusselt number against the increase of the thermal radiation parameter is increasing, and as the number of obstacles inside the cavity increases, the total Nusselt number increases.

Heat transfer analysis of MHD viscous nanofluid flow over a nonlinearly stretching sheet with heat source/sink: A numerical study

The present study analyses the magnetohydrodynamics (MHD) viscous nanofluid flow past a nonlinearly stretching sheet embedded in a porous medium under the influence of heat generation and thermal radiation. Further, variable magnetic field as well as variable permeability is used instead of constant magnetic field and permeability due to many therapeutic applications, which makes them distinctive and practically helpful. The MHD viscous flow and heat transfer equations have been generated as coupled second-order nonlinear partial differential equations using a mathematical model that resembles the physical flow problem. The partial differential equations governing the flow problems are reduced to ordinary differential equations via similarity variables. The reduced equations are then solved by Runge–Kutta–Fehlberg’s scheme with shooting method by the help of MATLAB software. The result obtained reveals that enhancing the heat generation parameter, porosity parameter, and radiation parameter upsurges the temperature of the nanofluid, whereas the magnetic parameter shows the reverse effect in the case of velocity distribution. Nusselt number decreases at the rate of 2.6147% for copper–water nanofluid when increased from 0 to 0.05. Silver nanoparticles have the highest heat transfer as compared to other nanoparticles. Because of this, silver nanoparticles are the most effective thermal conductors for increasing the effectiveness of heat storage in phase transition materials.

Influence of Chemical reaction and heat generation/absorption on Unsteady magneto Casson Nanofluid flow past a non-linear stretching Riga plate with radiation

The use of Casson fluid is of considerable importance in the manufacturing of pharmaceutical products, including the incorporation of china clay and biological fluids such as synovial liquids. Therefore, the primary objective of this work is to examine the characteristics of the Casson fluid flow. The Casson fluid is a non-Newtonian model often used to analyze the unsteady magnetohydrodynamic (MHD) heat and mass transfer in nanofluid flow scenarios across a non-linearly stretched Riga plate. The heat and mass transfer equations include the analysis of radiation and chemical reactions, respectively. Furthermore, the process of heat transmission is intensified by the existence of an external heat source or heat sink. By applying appropriate similarity transformations, the partial differential equations (PDEs) are converted into a set of nonlinear ordinary differential equations (ODEs). These ODEs are then solved numerically by utilizing the Runge-Kutta-Fehlberg-45 method, with the help of a shooting strategy. The validity of the study is determined by a comparative analysis of the present results in relation to prior research. The main objective of this research is to assess the influence of relevant flow parameters on the fluid flow, temperature, and concentration gradients, which will be visually represented and reported in tabular form. The augmentation of the Casson fluid coefficient (β) hinders the advancement of both velocity and temperature. The augmentation of the thermophoresis parameter (Nt) and magnetic factor (M) results in an elevation of θ(η) and a reduction in the curves depicting the volume fraction of nanoparticles. This study establishes a significant connection between many biological and engineering applications, particularly in the analysis of blood samples and the administration of drugs via blood circulation.

Evaluation of heat transfer transition for nanofluids within an enclosure based on magnetic field angles

The present simulation deals with Magnetohydrodynamics (MHD) with focus on heat transfer attributes with the addition of nanoparticle volume concentration (NVC). Influences of the governing parameters, including natural convection strength of Rayleigh number (Ra), magnetic field intensity of Hartmann number (Ha), and magnetic directions with a complete period of γ = 0°–180° are studied. The results disclose that MHD heat transfer patterns can be divided into three groups, i.e., Type-1 (Increase), Type-2 (Transition), and Type-3 (Optimum). With the increasing Ha, the heat convection is suppressed, resulting in Type-1. Enhancing Ra improves the thermal convection and thus leads to the occurrence of Type-3. In between, a critical Ha (Hacr) at a specific Ra exists for heat transfer transition (Type-2). The flow structure and heat transfer patterns vary with γ stemming from the Lorentz force component. The maximum stream function and best heat transfer rate are found at γ = 45°, corresponding to a higher Hacr for Type-2. For a wide range of Ra values, the combination of Ha2/Ra is adopted to describe the relationship between the Hacr and γ for the heat transfer transition with an empirical equation as Ra ≥ 5 × 104.