scholarly journals NUMERICAL STUDY OF MHD CONVECTIVE NANOFLUID FLOWS WITHIN A CORRUGATED TRAPEZOIDAL ENCLOSURE

2020 ◽  
Author(s):  
Victor Job ◽  
Sreedhara Rao Gunakala ◽  
P.V.S.N. Murthy ◽  
R. Panneer Selvam
Keyword(s):  
Microelectromechanical Systems ◽  
Numerical Study ◽  
Governing Equations ◽  
Nanofluid Flow ◽  
Single Walled Carbon Nanotube ◽  
Engineering And Technology ◽  
Side Walls ◽  
Pressure Projection ◽  
Trapezoidal Enclosure ◽  
Design And Manufacture

We consider the unsteady magnetohydrodynamic (MHD) natural convection flows of alumina (Al2O3)-water and single-walled carbon nanotube (SWCNT)-water nanofluids within a symmetrical corrugated trapezoidal enclosure with the effects of viscous and Joule dissipations. In this study, the corrugated bottom wall is isothermally heated, whereas the top wall is thermally insulated. The temperature of the side walls is fixed at the initial nanofluid temperature within the enclosure. We solve the governing equations for velocity and temperature, along with the corresponding initial and boundary conditions, using the polynomial pressure projection stabilized (PPPS) finite element method. The effects of sidewall inclination angle and Eckert number on nanofluid flow and convective heat transfer within the corrugated enclosure are examined. The results obtained from this study are important in various fields of engineering and technology, such as the design and manufacture of efficient heat exchangers and the cooling of microelectromechanical systems (MEMS) using nanofluids.

scholarly journals Marangoni convection of nanofluid in a wavy trapezoidal enclosure

2021 ◽  
Vol 25 (Spec. issue 2) ◽  
pp. 339-345
Author(s):  
Sharifah Nuriza Binti Syed Muhammad Al’Aidrus ◽  
Zailan Siri ◽  
Mohd Zubir
Keyword(s):  
Marangoni Convection ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Numerical Approach ◽  
The Finite Element Method ◽  
Governing Equations ◽  
Particle Volume ◽  
Nusselt Numbers ◽  
Side Walls ◽  
Trapezoidal Enclosure

The purpose of this study is to investigate the behaviour of natural convection in a wavy trapezoidal enclosure that is filled with nanofluid. The left wavy wall has wavelength, l, and amplitude, A. The top and bottom walls are adiabatic while the side walls are set to constant temperature, and shear stress occurs at the top of the enclosure. The numerical approach used in this study in order to discretize the governing equations with its boundary conditions is the finite element method where the Galerkin technique is adopted. The solutions obtained are for various values of the Marangoni number, Rayleigh number, and solid particle volume fraction. The graphs of the streamlines, isotherms, local Nusselt, and average Nusselt numbers are then presented and discussed.

A NUMERICAL STUDY OF FREE CONVECTIVE HEAT TRANSFER FROM A HEATED HALF-CYLINDER IN AN ENCLOSURE

1995 ◽  
Vol 19 (3) ◽  
pp. 285-300
Author(s):  
P.H. Oosthuizen ◽  
J.T. Paul
Keyword(s):  
Heat Transfer ◽  
Numerical Study ◽  
Boussinesq Approximation ◽  
Approximate Model ◽  
Governing Equations ◽  
Free Convective Flow ◽  
Wide Range ◽  
Fluid Properties ◽  
Different Temperatures ◽  
Side Walls

Two-dimensional free convective flow in an enclosure which has a heated half-cylinder on the floor has been numerically studied. The half-cylinder is kept at a uniform high temperature. The enclosure has horizontal upper and lower walls and inclined side-walls. The side-walls are also kept at uniform temperatures and the top and bottom surfaces are adiabatic. In general, the side-walls have been assumed to be at different temperatures. The situation considered is an approximate model of that which occurs in some simple crop dryers. The flow has been assumed to be steady and laminar. Fluid properties have been assumed constant except for the density change with temperature which has been treated using the Boussinesq approximation. The governing equations have been written in dimensionless form and solved using a finite element method. Results have been obtained for a wide range of the governing parameters for a Prandtl number of 0.7, i.e. for air, and the effects of these governing parameters on the heat transfer rate has been studied.

scholarly journals Numerical Study of the Turbulent Natural Convection in a Trapezoidal Cavity: Influence of the Inclination of the Lateral Walls

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Numerical Study ◽  
Boussinesq Approximation ◽  
Governing Equations ◽  
Square Cavity ◽  
Turbulent Natural Convection ◽  
Side Walls ◽  
Volume Method ◽  
Calculation Code

In this paper, we study the heat transfer in turbulent natural convection in a two- dimensional cavity with a trapezoidal section and isoscales filled out of air with as height H =2.5 m. In these conditions, the side walls are differentially heated while the horizontal walls are adiabatic. The k-ε turbulence model with a small Reynolds number was integrated in our calculation code. The governing equations of the problem were solved numerically by the commercial CFD code Fluent; which is based on the finite volume method and the Boussinesq approximation. The elaborated model is validated from the experimental results in the case of the turbulent flow in a square cavity. Then, the study was related primarily to the influence of the slope of the side walls of the cavity on the dynamic behavior and the heat transfer within the cavity.

scholarly journals Natural convection in a square cavity with partially active vertical walls: Time-periodic boundary condition

2006 ◽  
Vol 2006 ◽  
pp. 1-16 ◽  
Author(s):  
N. Nithyadevi ◽  
P. Kandaswamy ◽  
S. Sivasankaran
Keyword(s):  
Natural Convection ◽  
Numerical Study ◽  
Control Volume ◽  
Active Regions ◽  
Governing Equations ◽  
Square Cavity ◽  
Side Walls ◽  
Vertical Walls ◽  
Volume Method ◽  
Time Periodic

A numerical study of transient natural convection in a square cavity with partly thermally active side walls is introduced. The thermally active regions of the side walls are periodic in time. Top and bottom of the cavity are adiabatic. Nine different positions of the thermally active zones are considered. The governing equations are solved using control volume method with power-law scheme. The results are obtained for various values of amplitude, period, and Grashof numbers ranging from104–106and different thermally active situations. It is found that the average heat transfer increases by increasing amplitude forP=1,5, and decreasing forP=3. The average Nusselt number behaves nonlinearly as a function of period.

scholarly journals Numerical Study of Natural Convection of Biological Nanofluid Flow Prepared from Tea Leaves under the Effect of Magnetic Field

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1824
Author(s):  
Yacine Khetib ◽  
Ahmad Alahmadi ◽  
Ali Alzaed ◽  
Hussein A. Saleem ◽  
Mohsen Sharifpur ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Numerical Study ◽  
Control Volume ◽  
Simple Algorithm ◽  
Tea Leaves ◽  
Nanofluid Flow ◽  
Horizontal Magnetic Field ◽  
Side Walls ◽  
Strong Convection ◽  
Glycol Solution

The heat transfer of a biological nanofluid (N/F) in a rectangular cavity with two hot triangular blades is examined in this work. The properties used for nanoparticles (N/Ps) are derived from a N/P prepared naturally from tea leaves. Silver N/Ps are distributed in a 50–50 water/ethylene glycol solution. The cavity’s bottom wall is extremely hot, while the upper wall is extremely cold. The side walls are insulated, and the enclosure is surrounded by a horizontal magnetic field (M/F). The equations are solved using the control volume technique and the SIMPLE algorithm. Finally, the Nu is determined by changing the dimensions of the blade, the Rayleigh number (Ra), and the Hartmann number (Ha). Finally, a correlation is expressed for the Nu in the range of parameter changes. The results demonstrate that an increment in the Ra from 103 to 105 enhances the Nu more than 2.5 times in the absence of an M/F. An enhancement in the strength of the M/F, especially at the Ra of 105, leads to a dramatic reduction in the Nu. An increase in the height of the triangular blade intensifies the amount of Nu in weak and strong convection. The enlargement of the base of the triangular blade first enhances and then decreases as the Nu. The addition of 5% silver biological N/Ps to the fluid enhances the Nu by 13.7% in the absence of an M/F for high Ras.

Effect of Viscous Dissipation on MHD Williamson Nanofluid Flow in a Porous Medium

2019 ◽  
Vol 8 (3) ◽  
pp. 5795-5802 ◽  
Keyword(s):  
Porous Medium ◽  
Steady State ◽  
Numerical Solution ◽  
Viscous Dissipation ◽  
Flow Problem ◽  
Numerical Study ◽  
Steady State Flow ◽  
Nanofluid Flow ◽  
Shooting Technique ◽  
Order Four

The main objective of this paper is to focus on a numerical study of viscous dissipation effect on the steady state flow of MHD Williamson nanofluid. A mathematical modeled which resembles the physical flow problem has been developed. By using an appropriate transformation, we converted the system of dimensional PDEs (nonlinear) into coupled dimensionless ODEs. The numerical solution of these modeled ordinary differential equations (ODEs) is achieved by utilizing shooting technique together with Adams-Bashforth Moulton method of order four. Finally, the results of discussed for different parameters through graphs and tables.

scholarly journals Effect of magnetic field on nanofluid free convection in Conical Partially Annular Space

2020 ◽  
Vol 330 ◽  
pp. 01005
Author(s):  
Abderrahmane AISSA ◽  
Mohamed Amine MEDEBBER ◽  
Khaled Al-Farhany ◽  
Mohammed SAHNOUN ◽  
Ali Khaleel Kareem ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Hartmann Number ◽  
Volume Fraction ◽  
Boussinesq Approximation ◽  
Simulation Software ◽  
Comsol Multiphysics ◽  
Governing Equations ◽  
Element Analysis ◽  
Vertical Side ◽  
Side Walls

Natural convection of a magneto hydrodynamic nanofluid in a porous cavity in the presence of a magnetic field is investigated. The two vertical side walls are held isothermally at temperatures Th and Tc, while the horizontal walls of the outer cone are adiabatic. The governing equations obtained with the Boussinesq approximation are solved using Comsol Multiphysics finite element analysis and simulation software. Impact of Rayleigh number (Ra), Hartmann number (Ha) and nanofluid volume fraction (ϕ) are depicted. Results indicated that temperature gradient increases considerably with enhance of Ra and ϕ but it reduces with increases of Ha.

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