The Development of Free Convection Between Heated Vertical Plates

1962 ◽  
Vol 84 (1) ◽  
pp. 40-43 ◽  
Author(s):  
J. R. Bodoia ◽  
J. F. Osterle
Keyword(s):  
Heat Transfer ◽  
Finite Difference ◽  
Velocity Profile ◽  
Free Convection ◽  
Viscous Fluid ◽  
Heat Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Difference Form ◽  
Temperature And Pressure ◽  
Energy Equations

The development of free convection in a viscous fluid between heated vertical plates is investigated. The basic governing continuity, momentum, and energy equations are expressed in finite difference form and solved numerically on a digital computer. Results are obtained for the variations of velocity, temperature, and pressure throughout the flow field assuming the fluid to enter the channel with ambient temperature and a flat velocity profile. The flow and heat-transfer characteristics of the channel are studied and a development height established. A comparison is made between the results of this theoretical investigation and the experimental work of Elenbaas.

Effects of Dented Roughness on Laminar Flow and Heat Transfer in Microchannels

2010 ◽  
Author(s):  
Hui Miao ◽  
Yong Huang ◽  
Fa Xie ◽  
Haigang Chen ◽  
Fang Wang
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Working Fluid ◽  
Heat Transfer Characteristics ◽  
Nusselt Numbers ◽  
Flow And Heat Transfer ◽  
Micro Channels ◽  
Planar Area ◽  
Poiseuille Number ◽  
Energy Equations

Liquid laminar flow and heat transfer characteristics for parallel plate micro-channels consisting of many triangle shape hollows to fit with the etching surfaces are investigated numerically in the present paper. The height of the channel is 50μm, with three different relative depths, three relative spacing, and three oblique angles of the triangle surface, respectively. The 2D N-S and energy equations are solved using a commercial CFD code FLUENT6.3. Water is used as the working fluid, and the Reynolds number ranges from 100 to 1500. The global Poiseuille number and average Nusselt number are obtained. It is shown that the dented shapes cause a modest influence in Poiseuille number, but a greater impact on the Nusselt numbers. In addition, both of Po and Nu increase modestly with Re. The local Nusselt numbers are always lower in dented area and larger in planar area of dented roughness microchannels, than that of conventional smooth value. Finally, geometry parameters have modest impact on heat transfer for dented roughness.

Numerical analysis of free convection and entropy generation in a cavity using compact finite-difference lattice Boltzmann method

2019 ◽  
Vol 30 (2) ◽  
pp. 977-995 ◽  
Author(s):  
HamidReza KhakRah ◽  
Payam Hooshmand ◽  
David Ross ◽  
Meysam Jamshidian
Keyword(s):  
Heat Transfer ◽  
Rayleigh Number ◽  
Finite Difference ◽  
Free Convection ◽  
Lattice Boltzmann Method ◽  
Entropy Generation ◽  
Lattice Boltzmann ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Boltzmann Method

Purpose The purpose of this paper is to investigate the compact finite-difference lattice Boltzmann method is used to simulate the free convection within a cavity. Design/methodology/approach The finite-difference discretization method enables the numerical simulations to be run when there are non-uniform and curvilinear grids with a finer near-wall grid resolution. Furthermore, the high-order method is applied in the numerical approach, which makes it possible to go with relatively coarse mesh in respect to simulations, which used classical lattice Boltzmann method. The configuration of the cavity is set to sine-walled square. In addition, the cavity is filled with Al2O3-water nanofluid, and the Koo–Kleinstreuer–Li model is used to estimate the properties of nanofluid. Findings The nanoparticle (Al2O3) concentration in the base fluid (water) is considered in a range of 0-0.04. The nanofluid flow and heat transfer are investigated in laminar regime with Rayleigh number in the range of 103-106. The second law analysis is used to study the effects of different governing parameters on the local and volumetric entropy generation. The Rayleigh number, configuration of the cavity and nanoparticle concentration are considered as the governing parameters. The results are mainly focused on the flow structure, temperature field, local and volumetric entropy generation and heat transfer performance. Originality/value The originality of this study is using of a modern numerical method supported by an accurate prediction for nanofluid properties to simulate the flow and heat transfer during natural convection in a cavity.

scholarly journals Analysis of the flow and heat transfer characteristics for MHD free convection in an enclosure with a heated obstacle

2011 ◽  
Vol 16 (1) ◽  
pp. 89-99 ◽  
Author(s):  
S. Parvin ◽  
R. Nasrin
Keyword(s):  
Heat Transfer ◽  
Hartmann Number ◽  
Heated Wall ◽  
Convection Flow ◽  
Heat Transfer Characteristics ◽  
Natural Convection Flow ◽  
Square Enclosure ◽  
Thermal Fields ◽  
Flow And Heat Transfer ◽  
Energy Equations

Finite element method based on Galerkin weighted Residual approach is used to solve two-dimensional governing mass, momentum and energy equations for steady state, natural convection flow in presence of magnetic field inside a square enclosure. The cavity consists of three adiabatic walls and one constantly heated wall. A uniformly heated circular solid body is located at the centre of the enclosure. The aim of this study is to describe the effects of MHD on the flow and thermal fields in presence of such heated obstacle. The investigations are conducted for different values of Rayleigh number (Ra) and Hartmann number (Ha). Various characteristics of streamlines, isotherms and heat transfer rate in terms of the average Nusselt number (Nu) are presented for different parameters. The effect of physical parameter (D) is also shown here. The results indicate that the flow pattern and temperature field are significantly dependent on the above mentioned parameters.

Heat transfer from moving surfaces in a micropolar fluid

1999 ◽  
Vol 77 (6) ◽  
pp. 463-471 ◽  
Author(s):  
M A Mansour ◽  
A A Mohammadein ◽  
S MM El-Kabeir ◽  
RSR Gorla
Keyword(s):  
Heat Transfer ◽  
Micropolar Fluid ◽  
Free Stream ◽  
Plane Surface ◽  
Heat Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Layer Analysis ◽  
Convection Problem ◽  
Energy Equations ◽  
Flowing Stream

A boundary layer analysis is presented for the forced convection problem of a surface moving continuously in a flowing stream of a micropolar fluid. Two cases are considered, one corresponding to a plane surface moving in parallel with the free stream and the other, a surface moving in the opposite direction to the free stream. A similarity solution to the governing momentum, angular momentum, and energy equations is derived.These equations were solved numerically and the flow and heat transfer characteristics of the micropolar fluid are presented. PACS No.: 61.00

Effect of Variable Viscosity on Free Convection Flow in a Horizontal Porous Channel with a Partly Heated or Cooled Wall

2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Serban Rares Pop ◽  
Teodor Grosan ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Theoretical Study ◽  
Variable Viscosity ◽  
Porous Channel ◽  
Convection Flow ◽  
Heat Transfer Characteristics ◽  
Free Convection Flow ◽  
Viscosity Parameter ◽  
Flow And Heat Transfer

A theoretical study of the effect of variable viscosity on the steady free convection flow in a horizontal infinite porous channel when a part of its bottom wall is heated is presented in this paper. The transformed equations are solved numerically using a finite-difference method. The effects of the Rayleigh number and viscosity parameter on the flow and heat transfer characteristics are discussed.

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