• Energy Research
• SA close

The fundamental problem in electronic cooling systems is the implementation of a cavity such that it can be used to provide localized cooling to specific components, such as CPUs or GPUs, enhancing their performance and longevity. It can also be used in microfluidic devices for controlled drug delivery, where precise control of fluid flow is crucial. The present article numerically explores the free convection non-Newtonian Casson hybrid nanofluid phenomena that occur within an H-shaped cavity while heated from the middle. The heating efficiency and heat flow in a cavity are influenced by perpendicular hot walls that connect two vertical closed channels. A numerical solution is obtained by implementing the Galerkin finite element method to solve the partial differential equation. The numerical outcomes are depicted on the contour of streamlines and isotherms for different parameters in the following ranges: 0.1 ≤ η ≤ 0.4, 0.005≤ϕhp≤0.020, 0.1 ≤ γ ≤ 2, and 103 ≤ Ra ≤ 106 at fixed Pr = 6.2. In addition, line graphs show rate of heat transfer within the enclosure using the average Nusselt number for these parameters. Increased aspect ratios (η = 0.4) result in a minimal rate of heat transfer enhancement, whereas decreasing η leads to a significantly higher average Nusselt number and maximum heat transfer within the cavity. The convective rate of heat transfer increases with the presence of hybrid nanoparticles inside an H-shaped cavity for all Rayleigh numbers. The rotation of the Casson hybrid nanofluid also rises as the volume ratio of nanoparticles increases. For a fixed aspect ratio (A.R) of 0.1, the heat dissipation is 6.91% at a lower ϕhp value of 0.005 at a fixed Ra value of 105. However, it increases to 7.072% for a higher ϕhp value of 0.02 at Ra = 105. With increasing Ra number, ϕhp, and γ, the number NuAve increases.

In this paper, we discussed the Cu - Al2O3/H2O (Hybrid nanofluid) flow over permeable exponentially stretching channel. The hybrid nanofluid involves two kinds of nanoparticles along with base fluid (pure water). Our research objective is to evaluate the heat transfer rate of hybrid nanofluid.The resulting system is numerically tackled via shooting method (bvp4c).The hybrid nanofluid gains larger rate of heat transfer as compared to simple nanofluid. The impact of non-dimension parameter on temperature profile, boundary layer will be analyzed for enormous values of dimensionless parameter. Also, boundary layer thickness when γ 0 (suction) will be compared. The present results with the existence literature will be compared for justification/validation.

This analysis deals the steady and the incompressible MHD fluid flow by sinusoidal walls of a hexagonal cavity with a cylindrical obstacle at the center. Finite element method (FEM), a numerical modeling method is used to examine the heat transfer and fluid flow controlled by the energy equation, the continuity equation and Navier-Stokes equations, which are converted to dimensionless form through suitable parameterization, which are tackled by finite element method. The temperature distribution and velocity fields are displayed for various parameters which are Richardson number, Hartmann number, Reynolds number, velocities’ amplitudes ratio, temperatures’ amplitudes ratio and phase deviation. This graphical study shows good convergent results of temperature and velocity for variation of involved parameters. At the end, the significant effects of the heat transfer rate are discussed in terms of the Nusselt number.

Abstract The performance of friction drag, heat transfer rate, and mass transfer is illustrated the in boundary layer flow region via density of motile microorganisms. Magnetic dipole in presence of Curie temperature and density of motile microorganisms plays important role in stabilizing and controlling the momentum and thermal boundary layers. In this direction, the characteristics of the magnetic dipole on the suspensions of motile microorganisms in the flow of ferrofluid are incorporated. Heat flux in the suspensions of motile microorganisms and at the surface is computed via Fourier's law of heat conduction. Characteristics of sundry physical parameter on the ferrohydrodynamic, thermal energy, mass transfer, and bioconvection are computed numerically and analytically. It is depicted that an enhancement in thermal Rayleigh number results in the reduction of friction drag, thereby enhances the heat transfer rate and Sherwood number at the surface, while the local density of motile microorganisms enhance for larger values of bioconvection Lewis number. Further, it is characterized that bioconvection Rayleigh number has increasing behavior on the heat transfer in the boundary layer. Comparison with available results are found in an excellent agreement.

The present study communicates with the thermal analysis of an incompressible micropolar fluid by considering two different prescribed conditions corresponding to two different surfaces. On the porous surface of two different stretchable sheets, the unsteady flow problem of a micropolar fluid is explored by taking the variable impacts of the magnetic field. For both considered sheets, the prescribed thermal analysis is carried out with the contribution of joule heating, viscous dissipation, and radiation. Two prescribed cases of surface temperature and heat flux are discussed for linear stretched surface. Similarly, prescribed cases of exponential surface temperature and exponential heat flux are investigated for the case of an exponential stretchable surface. An effective technique of bvp4c in MATLAB is utilized to numerically tackle the governing equations of the problem. Both the distributions of temperature and velocity and the field of microrotation are graphically scrutinized relative to different geometries and several pertinent parameters. This study of thermal analysis with prescribed conditions elucidates that for an exponential surface, three distributions of flow phenomenon (temperature, microrotation, velocity) manifest more prominent results in comparison to the stretchable surface with linear velocity.

Objective: In this paper, we consider a model that describes the ciliary beating in the form of metachronal waves along with the effects of Magnetohydrodynamic fluid over a curved channel with slip effects. This work aims at evaluating the effect of Magnetohydrodynamic (MHD) on the steady two dimensional (2-D) mixed convection flow induced in carbon nanotubes. The work is done for both the single wall nanotube and multiple wall nanotube. The right wall and the left wall possess a metachronal wave that is travelling along the outer boundary of the channel. Methods: The wavelength is considered very large for cilia induced MHD flow. The governing linear coupled equations are simplified by considering the approximations of long wavelength and small Reynolds number. Exact solutions are obtained for temperature and velocity profiles. The analytical expressions for the pressure gradient and wall shear stresses are obtained. The term for pressure rise is obtained by applying Numerical integration method. Results: Numerical results of velocity profile are mentioned in a table form, for various values of solid volume fraction, curvature, Hartmann number [M] and Casson fluid parameter [ζ]. The final section of this paper is devoted to discussing the graphical results of temperature, pressure gradient, pressure rise, shear stresses and stream functions. Conclusion: Velocity profile near the right wall of the channel decreases when we add nanoparticles into our base fluid, whereas the opposite behaviour is depicted near the left wall due to ciliated tips, whereas the temperature is an increasing function of B and γ and a decreasing function of Φ.

The influence of hybrid nano-fluid on heat transport in a semi-annular channel is investigated numerically. The hybrid nano-fluid is a liquid water with suspension of SWCNT and MWCNT. Constant heat fluxes are applied to the walls of channel. The finite volume approach is used to solve the governing mathematical equations. The volume percent of SWCNT is fixed at 0.01% and the volume fraction of MWCNT is varied from 0.01% to 0.1%. Heat transport is shown to diminish as the volume fraction of MWCNT increases. The heat transferred from the wall to the near fluid is influenced by the curvature of the walls. The results are displayed as velocity contours and isotherms. For certain volume fractions of nanoparticles, local Nusselt number distributions are given. It has been discovered that walls with a smaller curvature have a stronger convection heat transfer. Pressure is increased when the volume percentage of nanoparticles increases.

AbstractThe flow of hybrid nanoparticles with significant physical parameters with different base fluids in the presence of Biot number, velocity slip, and MHD effects has not been explored so far, particularly for a circular cylinder. Therefore, the current report is presented to offer a numerical solution for hybrid nanoparticles with base fluids (water and ethylene glycerol) via a circular cylinder. The physical situation is interpreted in terms of partial differential equations and is converted into ordinary differential equations after applying the similarity transformation. The results are presented in both tabular and graphical forms. The impact of physical parameters on velocity distribution is examined through graphs. The comparative results of hybrid nanoparticles for distinct base fluids as ethylene glycol and water are proposed and the hybrid nanoparticles with base fluid water seems to be greater than that of the hybrid nanoparticles with base fluid EG. The temperature profile of hybrid nanoparticles is found to be a decreasing function with growth in velocity slip parameter but an opposite trend is noted in case of nanoparticles . The skin friction and Nusselt number augmented for the increase in magnetic field, velocity slip, and nanoparticle while it shows a decreasing trend toward thermal slip parameter. For the both cases, improvement in Biot number helps enhance the heat transfer constantly.

AbstractWe considered the magnetized micro polar fluid with hybrid nanomaterial flow over a curved stretching surface. We discussed the effects of single wall carbon nanotube and multiwall carbon nanotube with base fluids (water and propylene glycol). Under the flow assumptions, we developed the mathematical model and applied the boundary layer approximations to reduce the system of partial differential equations. Further, the suitable similarity transformations are applied on the partial differential equations to make dimensionless system. The dimensionless system solved by means of numerical scheme via bvp4c shooting methods. Involving the dimensionless physical parameters effects are highlighted in the form of graphs and tables. Additionally, significant physical quantities i.e. Nusselt number, Couple stress coefficient and Skin friction coefficient are also presented and evaluated numerically. These results are more important which may use in the field of engineering and industrial.