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Article
Publication date: 1 May 1994

A. Nag, A. Sarkar and V.M.K. Sastri

The effect of a horizontal partial porous partition on heat transfer andflow structure in a differentially heated square cavity is investigated.While the fluid flow is…

Abstract

The effect of a horizontal partial porous partition on heat transfer and flow structure in a differentially heated square cavity is investigated. While the fluid flow is assumed to be governed by Navier—Stokes equations, fluid saturated porous media is assumed to be governed by Darcy’s equations. Standard Galerkin method of finite element formulation is applied for discretization of the system of equations. The non‐linearities in the discretized equations are treated with Newton‐Raphson scheme. The code developed is tested for validation for modified Rayleigh number Ra up to 400. The code is then applied to a differentially heated square cavity with a horizontal partial porous partition. While the thickness of the porous partition is found to have appreciable effect on heat transfer and flow field, width of the porous partition is found to have insignificant bearing on heat transfer except when the partition is very small and compatible to the thickness of the boundary layer developed. During the experimentation Darcy number and Rayleigh number are assumed to be constant at 10–4 and 106 respectively.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 4 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 March 1992

P.K. GHOSH, A. SARKAR and V.M.K. SASTRI

Natural convection in a square cavity with a centrally located partition is considered. While one of the side walls is fully active, the other is partly insulated…

Abstract

Natural convection in a square cavity with a centrally located partition is considered. While one of the side walls is fully active, the other is partly insulated. Numerical simulation, based on the finite element method, has been carried out for different lengths of the active surface. The results have been compared with the cases when the cavity is without partition as well as the case of a partitioned cavity with fully active side walls.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 2 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 March 1993

R.K. SAHOO, A. SARKAR and V.M.K. SASTRI

The effect of a rectangular obstruction of different sizes on natural convection heat transfer in the case of a vertical channel has been analysed for T boundary…

Abstract

The effect of a rectangular obstruction of different sizes on natural convection heat transfer in the case of a vertical channel has been analysed for T boundary conditions on the walls. A comparison of the Nusselt number values with those for plane channel is presented. For smaller obstruction depths and for asymmetric heating, there is not much variation of the results from a case of channel with a baffle for asymmetric heating. For large obstruction depths, the flow conditions show a behaviour similar to that of a channel with a backward‐facing step.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 3 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 29 May 2019

Nikita Gibanov and Mikhail A. Sheremet

The purpose of this paper is to investigate natural convective heat transfer in a cubical cavity with the heat source of a trapezoidal form having a constant temperature.

Abstract

Purpose

The purpose of this paper is to investigate natural convective heat transfer in a cubical cavity with the heat source of a trapezoidal form having a constant temperature.

Design/methodology/approach

The domain of interest is a cubical cavity with two isothermal opposite vertical walls, while other walls are adiabatic. A discrete heater of a trapezoidal shape is located at the bottom wall of the cavity. Governing equations formulated in dimensionless vector potential functions, vorticity vector and temperature with corresponding initial and boundary conditions have been solved numerically using a developed computational code based on the finite difference method.

Findings

The results show that the variation of geometric parameters, such as height, length and size of the local heater, significantly influences the evolution of a temperature field and fluid flow inside the enclosure. The effects of Rayleigh number and time on streamlines, isotherms and average Nusselt number have been studied.

Originality/value

The originality of this work is to explore three-dimensional (3D) natural convection in a cubical cavity with a local heat source of trapezoidal shape, to analyze the effects of heater geometric parameters and to compare obtained 3D data with two-dimensional results.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 June 1999

S.K. Mahapatra, S. Sen and A. Sarkar

A finite element solution on the interaction of surface radiation and variable property laminar natural convection is presented. Finite element formulation of the…

Abstract

A finite element solution on the interaction of surface radiation and variable property laminar natural convection is presented. Finite element formulation of the governing equations, associated with variable property natural convection, and incorporation of the radiative boundary conditions has been extensively discussed. The study also aims to highlight the limiting value of the terminal temperature difference (TTD), below which the natural convection heat transfer becomes the sole heat transfer mode, i.e. the effect of surface radiation can be neglected. The effects of variations of emissivity and TTD are also presented.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 9 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 July 1995

Swarnendu Sen and A. Sarkar

The interaction of variable property convection and surface radiation ina differentially heated square cavity is considered. Effect of surfaceradiation on natural…

Abstract

The interaction of variable property convection and surface radiation in a differentially heated square cavity is considered. Effect of surface radiation on natural convection has been studied from the point of view of flow structure and isotherm patterns. Wherever possible, a comparative study has been invoked between the outcome of the present work and the constant property formulation. The finite element method has been used in the present work and associated formulation schemes have been described in detail.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 5 no. 7
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 9 January 2020

Lei Wang, Yang Cai, Wei-Wei Wang, Run-Zhe Liu, Di Liu, Fu-Yun Zhao and Hanqing Wang

This paper aims to numerically investigate the magnetohydrodynamic (MHD) convection heat transfer of nanofluid inside a differentially heated enclosure with various fin…

Abstract

Purpose

This paper aims to numerically investigate the magnetohydrodynamic (MHD) convection heat transfer of nanofluid inside a differentially heated enclosure with various fin morphologies.

Design/methodology/approach

The fluid flow within the cavity was governed by N-S equations while it within porous medium was solved by the non-Darcy model, called the Darcy–Forchheimer model based on representative element-averaging method. Empirical correlations from experimental data are used to evaluate the effective thermal conductivity and dynamic viscosity. Relevant governing parameters, including thermal Rayleigh number (105-107), Hartmann number (0-50), Darcy number (10−6-10−1), thermal conductivity ratio of porous matrix (1-103), nanoparticles volume fraction (0-0.04) and topology designs of porous fins, are sensitively varied to identify their effects and roles on the fluid flow and heat transfer. Particularly, heatlines are used to investigate the mechanism of heat transport.

Findings

Numerical results demonstrate that the predictions of average Nusselt number are augmented by using more porous fins with high permeability, and this effect becomes opposite in tiny Darcy numbers. Particularly, for high Darcy and Rayleigh numbers, the shortest fins could achieve the best performance of heat transfer. In addition, the prediction of average Nusselt number reduces with an increase in Hartmann numbers. An optimal nanoparticles concentration also exists to maximize heat transfer enhancement. Finally, numerical correlations for the average Nusselt number were proposed as functions of these governing parameters.

Practical implications

Present work could benefit the thermal design of electronic cooling and thermal carriers in nanofluid engineering.

Social implications

Present work could benefit the thermal design of electronic cooling and thermal carriers in nanofluid engineering. In addition, optimum thermal removals could enhance the lifetime of electronics, therefore reducing the cost of energy and materials.

Originality/value

To the best knowledge of authors, there are not any studies considering the synergetic effects of porous fins on MHD convection of nanofluids. Present work could benefit the thermal design of electronic cooling and thermal carriers in nanofluid engineering.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 22 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 4 January 2016

Abderrahim Bourouis, Abdeslam Omara and Said Abboudi

The purpose of this paper is to provide a numerical study of conjugate heat transfer by mixed convection and conduction in a lid-driven enclosure with thick vertical…

Abstract

Purpose

The purpose of this paper is to provide a numerical study of conjugate heat transfer by mixed convection and conduction in a lid-driven enclosure with thick vertical porous layer. The effect of the relevant parameters: Richardson number (Ri=0.1, 1, 10) and thermal conductivity ratio (Rk=0.1, 1, 10, 100) are investigated.

Design/methodology/approach

The studied system is a two dimensional lid-driven enclosure with thick vertical porous layer. The left vertical wall of the enclosure is allowed to move in its own plane at a constant velocity. The enclosure is heated from the right vertical wall isothermally. The left and the right vertical walls are isothermal but temperature of the outside of the right vertical wall is higher than that of the left vertical wall. Horizontal walls are insulated. The governing equations are solved by finite volume method and the SIMPLE algorithm.

Findings

From the finding results, it is observed that: for the two studied cases, heat transfer rate along the hot wall is a decreasing function of thermal conductivity ratio irrespective of Richardson numbers contrary to the heat transfer rate along the fluid-porous layer interface which is an increasing function of thermal conductivity ratio. At forced convection dominant regime, the difference between heat transfer rate for upward and downward moving wall is insensitive to the thermal conductivity ratio. For downward moving wall, average Nusselt number is higher than that of upward moving wall.

Practical implications

Some applications: building applications, furnace design, nuclear reactors, air solar collectors.

Originality/value

From the bibliographic work and the authors’ knowledge, the conjugate mixed convection in lid-driven partially porous enclosures has not yet been investigated which motivates the present work that represent a continuation of the preceding investigations.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 26 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 November 1998

A. Mezrhab and L. Bchir

The heat transfer by radiation and natural convection in a two‐dimensional, air‐filled square enclosure with a vertical partition of finite thickness and varying height…

Abstract

The heat transfer by radiation and natural convection in a two‐dimensional, air‐filled square enclosure with a vertical partition of finite thickness and varying height was investigated numerically in the laminar regime. The horizontal end walls are assumed to be adiabatic, and the vertical walls are at different temperatures. Calculations are made by using a finite volume method and an efficient numerical procedure is introduced for calculating the view factors, with shadow effects included. The results indicate that the partition does not significantly modify the heat transfer rate through the cavity, especially at high Rayleigh numbers, provided that its height is less than 90 per cent of the cavity height. The effects of radiation on the velocity and the temperature fields and the overall heat transfer rates as a function of the widths of the vents, solid/fluid conductivity ratio and Rayleigh number are documented.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 8 no. 7
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 22 May 2007

Kamil Kahveci

This paper seeks to investigate the effect of a heat conducting vertical partition in an enclosure on natural convection heat transfer and fluid flow using the…

Abstract

Purpose

This paper seeks to investigate the effect of a heat conducting vertical partition in an enclosure on natural convection heat transfer and fluid flow using the polynomial‐based differential quadrature (PDQ) method.

Design/methodology/approach

The PDQ method with the non‐uniform Chebyshev‐Gauss‐Lobatto grid point distribution given below is used to transform the governing equations into a set of algebraic equations. After numerical discretization, the resulting algebraic equations are solved by the successive over‐relaxation iteration method.

Findings

It is found that the average Nusselt number decreases towards a constant value as the partition is distanced from the hot wall towards the middle of the enclosure. Furthermore, with decreasing thermal conductivity ratio, the average Nusselt number first increases and passes a peak point and then begins to decrease. The average heat transfer rate exhibits little dependence on the width of the partition in the range taken into consideration in this study for the thickness of the partition.

Originality/value

This study offers more knowledge on natural convection in partitioned enclosures.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 17 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

1 – 10 of 376