Numerical Analysis of Unsteady Hybrid Nanofluid Flow Comprising CNTs-Ferrousoxide/Water with Variable Magnetic Field

The introduction of hybrid nanofluids is an important concept in various engineering and industrial applications. It is used prominently in various engineering applications, such as wider absorption range, low-pressure drop, generator cooling, nuclear system cooling, good thermal conductivity, heat exchangers, etc. In this article, the impact of variable magnetic field on the flow field of hybrid nano-fluid for the improvement of heat and mass transmission is investigated. The main objective of this study is to see the impact of hybrid nano-fluid (ferrous oxide water and carbon nanotubes) CNTs-Fe3O4, H2O between two parallel plates with variable magnetic field. The governing momentum equation, energy equation, and the magnetic field equation have been reduced into a system of highly nonlinear ODEs by using similarity transformations. The parametric continuation method (PCM) has been utilized for the solution of the derived system of equations. For the validity of the model by PCM, the proposed model has also been solved via the shooting method. The numerical outcomes of the important flow properties such as velocity profile, temperature profile and variable magnetic field for the hybrid nanofluid are displayed quantitatively through various graphs and tables. It has been noticed that the increase in the volume friction of the nano-material significantly fluctuates the velocity profile near the channel wall due to an increase in the fluid density. In addition, single-wall nanotubes have a greater effect on temperature than multi-wall carbon nanotubes. Statistical analysis shows that the thermal flow rate of (Fe3O4-SWCNTs-water) and (Fe3O4-MWCNTs-water) rises from 1.6336 percent to 6.9519 percent, and 1.7614 percent to 7.4413 percent, respectively when the volume fraction of nanomaterial increases from 0.01 to 0.04. Furthermore, the body force accelerates near the wall of boundary layer because Lorentz force is small near the squeezing plate, as the current being almost parallel to the magnetic field.

Implications of Multiple Numerical Aspects for Carreau Nanofluids With Heat Generation/absorption via Nonuniform Channels

Nanomaterials are unique work fluids with preeminent thermal performance for improving heat dissipation. We present theoretical and mathematical insights into nanofluid heat transfer and flow dynamics in nonuniform channels utilizing a non-Newtonian fluid. Therefore, the impacts of heat absorption/generation and Joule heating in a magneto hydrodynamic flow of a Carreau nanofluid into a convergent channel with viscous dissipation are addressed in this mathematical approach. Brownian and thermophoresis diffusion are considered to investigate the behavior of temperature and concentration. The magnetic effects on the flow performance are measured. The leading nonlinear equations are solved numerically using the BVP4c solver and RK-4 (Runge–Kutta) along with the shooting algorithm using the computer software MATLAB. The obtained dual solutions are presented graphically. The consequences of the variable magnetic field, heat absorption/generation and numerous physical parameters on the temperature and concentration field are surveyed. The outcomes show that increasing the rates of the heat absorption/generation parameter and Eckert number enhances the thickness of the thermal profile of the convergent channels, while increasing the value of the Prandtl number expands the thickness of the momentum boundary layer of the convergent channels. The key findings related to the study models are presented and discussed. An assessment of solutions achieved in this article is made with existing data in the literature.

Magnetic stimulation in the treatment of postherpetic neuralgia – a case report

Herpes zoster (shingles) is an acute infectious viral disease that may develop in individuals who have previously had chickenpox. Unlike chickenpox, shingles is more likely to occur in adults, with the risk increasing with age. The paper presents treatment outcomes in a 63-year-old patient with severe thoracic pain persisting for 5 weeks. The treatment included 15 sessions of magnetic stimulation using a low induction variable magnetic field, performed once a day, which allowed to significantly reduce pain, as assessed using the Laitinen Pain Scale. The inclusion of magnetic stimulation as an element of comprehensive therapy also improved the patient’s quality of life, as assessed with EuroQol (a score of 25 before the therapy vs. 65 after the therapy).

Combined Effects of Sequential Velocity and Variable Magnetic Field on the Phase Change Process in a 3D Cylinder Having a Conic-Shaped PCM-Packed Bed System

Effects of sequential velocity and variable magnetic field on the phase change during hybrid nanofluid convection through a 3D cylinder containing a phase-change material packed bed (PCM-PB) system is analyzed with the finite element method. As the heat transfer fluid, 40% ethylene glycol with hybrid TiO2-Al2O3 nanoparticles is considered. Impacts of the sequential velocity parameter (K, between 0.5 and 1.5), geometric factor of the conic-shaped PCM-PB (M, between 0.2 and 0.9), magnetic field strength (Ha number between 0 and 50) and solid volume fraction of hybrid nanoparticles (vol.% between 0.02% and 0.1%) on the phase change dynamics are explored. Effects of both constant and varying magnetic fields on the phase change process were considered. Due to the increased fluid velocity at the walls, the phase change becomes higher with higher values of the sequential velocity parameter (K). There is a 21.6% reduction in phase transition time (tF) between the smallest and highest values of K both in the absence and presence of a constant magnetic field. The value of tF is reduced with higher magnetic field strength and the amount of reduction depends upon the sequential velocity parameter. At K = 1.5, the reduction amount with the highest Ha number is 14.7%, while it is 26% at K = 0.5. When nanoparticle is loaded in the base fluid, the value of tF is further reduced. In the absence of a magnetic field, the amount of phase-transition time reduction is 6.9%, while at Ha = 50, it is 11.7%. The phase change process can be controlled with varying magnetic field parameters as well. As the wave number and amplitude of the varying magnetic field are considered, significant changes in the tF are observed.

Influences of Marangoni Convection and Variable Magnetic Field Hybrid Nanofluid Thin Film Flow past a Stretching Surface

The investigations about thin-film flow play a vital role in the field of optoelectronics and magnetic devices. Thin films are reasonably hard and thermally stable but are more fragile. The thermal stability of thin film can be further improved by incorporating the effects of nanoparticles. In the current work, a stretchable surface is considered upon which hybrid nanofluid thin-film flow is taken into account. The idea of augmenting heat transmission is focused in current work by making use of hybrid nanofluid. The flow is affected by variations in the viscous forces along with viscous dissipation effects and Marangoni convection. A time-constrained magnetic field is applied in the normal direction to the flow system. The equations governing the flow system are shifted to a non-dimensional form by applying similarity variables. The homotopy analysis method (HAM) has been employed to find the solution of resultant equations. It has been noticed in this study that, the flow characteristics decline with augmentation in magnetic, viscosity, and unsteadiness parameters while grow up with enhancing values of thin-film parameter. Thermal characteristics are supported by the growing values of the Eckert number and unsteadiness parameter while opposed by the viscosity parameter and Prandtl number. The numerical impact of different emerging parameters upon skin friction and Nusselt number has been calculated in tabular form. A comparison of current work with established result has carried out with a good agreement in both results.

Significance of Thermophoretic and Brownian Motion on MHD Nanofluids Flow towards a Circular Cylinder under the Inspiration of Multiple Slips: An Industrial Application

In this article, MHD flow of silver/water nanofluid past a stretched cylinder under the impact of thermal radiation with chemical reaction and slip condition is studied. The impact of Soret and Dufour effect is also analyzed during this flow. The uniqueness of the given problem is enlarged with the insertion of variable magnetic field, free stream velocity, thermal slip condition, and nonlinear thermal radiation. The PDEs are converted to ODEs by using suitable similarity transformation. The nonlinear system of ODEs is solved by applying convergent homotopy analysis method (HAM). The velocity, temperature, and concentration profiles for the free stream and at the plate are discussed through graphs and numerical tables. It is found that velocity field reduces, while the temperature profile rises for the increasing values of magnetic parameter. It is examined that effects of curvature on frication factor are increasing. Furthermore, temperature profile increases for greater Brownian motion and thermophoresis parameters. Transfer of heat enhances decreasing the radius of the cylinder also with heat generation parameter. The skin friction can be reduced by enhancing free stream and wall stretching velocities ratio. Velocity profile of the flow can be controlled by enhancing velocity slip and magnetic field.

Dufour and Soret Effect on Viscous Fluid Flow between Squeezing Plates under the Influence of Variable Magnetic Field

The aim of this article is to investigate the effect of mass and heat transfer on unsteady squeeze flow of viscous fluid under the influence of variable magnetic field. The flow is observed in a rotating channel. The unsteady equations of mass and momentum conservation are coupled with the variable magnetic field and energy equations. By using some appropriate similarity transformations, the partial differential equations obtained are then converted into a system of ordinary differential equations and are solved by Homotopy Analysis Method (HAM). The influence of the natural parameters are investigated for the velocity field components, magnetic field components, heat and mass transfer. A direct effect of the squeeze Reynold number is observed on both concentration and temperature. Moreover, increasing the magnetic Reynold number shows an increase in the fluid temperature, but in the case of concentration, an inverse relation is observed. Furthermore, a decreasing effect of the Dufour number is observed on both concentration and temperature distribution. Besides, in case of the Soret number, a direct effect is observed on concentration, but an inverse effect can be seen on temperature distribution. Different effects are shown through graphs in this study and an error analysis is also presented through tables and graphs.