Computational Fluid Dynamics (CFD) Analysis of Buoyancy Flow in A Differentially Heated Square Cavity

Isiaka

Al‐Farhany

et al. 2022

JERA

Numerical study of natural convection around a heated trapezoidal block of different sizes located centrically in a larger trapezium has been investigated. The annulus between the trapeziums is filled with porous media. The sides of the inner trapezium are heated to a fixed temperature (T_h), and the slanted walls of the outer trapezium are adiabatic while its upper and lower walls are heated to temperatures of 〖T_c+(T_h-T_c)sin〗⁡(πx⁄L) and 〖T_h+(T_h-T_c)sin〗⁡(πx⁄L) respectively. The finite element numerical approach was used to solve the relevant dimensionless equations. Results are gotten for salient parameters including; modified Rayleigh number (10≤Ra_m≤ 1000), Darcy number (10^(-5)≤Da≤ 10^(-2)), and area ratio (1/5≤AR≤ 1/3). The results of this study are shown as isothermal contours, stream functions, and average Nusselt number. The results show that increasing Ra_m improves heat transfer; however, the response of thermal characteristics to AR increment depends on the range of Darcy number considered. Results from this study find application in ingot treatments and microchannel cooling among others.

Section: Introductionmentioning

confidence: 77%

Numerical Analysis of Natural Convection in a Concentric Trapezoidal Enclosure Filled with a Porous Medium

Isiaka

Al‐Farhany

et al. 2022

JERA

“…It was indicated that internal heat generation promoted heat transfer, while heat absorption discouraged heat transfer enhancement. Olayemi et al 24 reported the effects of Prandtl and Rayleigh numbers in a square domain subjected to different heating modes and driven by buoyancy forces. They reported the relationship between Nusselt and Rayleigh numbers, and that low Prandtl number fluids (like, air and water) are preferred in achieving a very high heat transfer rate than fluids of high Prandtl numbers, which are expensive but result in an insignificant increase in heat transfer enhancement when compared with fluids of low Prandtl number.…”

Section: Introductionmentioning

confidence: 99%

Parametric studies of mixed convective fluid flow around cylinders of different cross‐sections

Obalalu²,

Ibitoye

et al. 2023

Heat Trans

A numerical study of mixed convective heat transfer in a lid‐driven square enclosure containing a hot elliptic cylinder is conducted. The impacts of the Grashof number , Reynolds number , cylinder tilt angle , and aspect ratio have been examined for a fluid of of 0.71. The horizontal enclosure walls are insulated, while its vertical walls are restricted to a nonvarying temperature Tc, whereas a sinusoidal temperature of is imposed on the wall of the elliptical cylinder. The governing equations are solved using COMSOL Multiphysics 5.6 software. The fluid dynamic and the heat transport profiles between the enclosure and the elliptical cylinder walls are represented by the stream function, isothermal contours, and average Nusselt number. Results established that for all the considered aspect ratios, the thermal heating range of is predominantly a conduction mechanism. The critical position of the ellipse where the inclination effect becomes insignificant is determined by the Grashof number and aspect ratio when the Re = 100. The strength of vortices and cell numbers are significantly influenced by the aspect ratio, particularly when the . When , the average heat transfer from the cylinder remains the same regardless of the cylinder's orientation. The impact of cylinder orientation on heat transfer from the cylinder wall is minimal for . For AR values of , increasing the inclination angle does not result in improved heat transfer. The influence of the increasing inclination angle on the right wall diminishes as the angle increases, except when the Grashof number is greater than 105, where the rate of heat transfer is enhanced for inclination angles beyond 45°.

“…However, with double-diffusive natural convection, increasing the Grashof number increases average Nu and the overall heat transfer rate [38]. The implications of Rayleigh number and geometric parameters on natural and mixed convective heat transfer in relevant enclosures were emphasized [39][40][41][42][43][44][45][46][47]. Salari et al [48] conducted a numerical study to determine the influence of turbulent transient models on natural convection in trapezoidal cavities.…”

Section: Introductionmentioning

confidence: 99%

Mixed Convective Heat Transfer in a Lid-Driven Concentric Trapezoidal Enclosure: Numerical Simulation

Al‐Farhany

Ibitoye

et al. 2022

JERA

This study investigates the implications of the area ratio (AR) and Grashof number (Gr) on fluid flow properties and heat transfer due to mixed convection around heated trapezoidal blocks located concentrically inside a larger trapezium driven by a lid. The outer trapezium's upper and lower horizontal walls are moving in opposite directions. The model developed was solved using the finite element technique. The inner walls of the trapezium are retained at an isothermal temperature, while the slanted outer walls of the trapezium are perfectly insulated. The upper and lower walls of the enclosure are subjected to normalized sinusoidal temperatures. Grashof number in the range of 103£Gr£105 and area ratios ( ) of , and were investigated. The simulation outcomes are displayed as stream function, isothermal contours, and local Nusselt number. Considering the interval of for the inner block, the Nusselt number increase with diminishing area ratio for the upper wall, while the response of the lower wall to Gr variation is a function of the AR considered. At the bottom wall of the outer trapezium, results showed that the rate of heat transfer was not significantly affected by changes in area ratio. Furthermore, as the AR reduces, the heat transmission along the top wall of the outer trapezium improves with the Grashof number, with the least and peak heat transfer enhancements occurring at 50 % and 100 % percent of the wall length, respectively.