On the effect of porous thick horizontal partial partition attached to one of the active walls of a differentially heated square cavity
01 May 1994-International Journal of Numerical Methods for Heat & Fluid Flow (MCB UP Ltd)-Vol. 4, Iss: 5, pp 399-411
TL;DR: In this article, the effect of a horizontal partial porous partition on heat transfer and flow structure in a differentially heated square cavity is investigated, where the fluid flow is assumed to be governed by Navier-Stokes equations and fluid saturated porous media is governed by Darcy's equations.
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 experime...
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44 citations
TL;DR: In this article, a new lattice Boltzmann (LB) approach was developed to overcome the difficulty of conjugate problems on fluid-porous interfaces, which is validated by three benchmark tests.
33 citations
TL;DR: In this article, the authors provided a numerical study of conjugate heat transfer by mixed convection and conduction in a lid-driven enclosure with thick vertical porous layer, and the effect of the relevant parameters: Richardson number (Ri=0.1, 1, 10, 100) and thermal conductivity ratio (Rk = 0.
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 wa...
6 citations
TL;DR: In this paper , the authors presented the numerical analysis of exergy transfer and irreversibility through the discrete filling of high-porosity aluminum metal foams inside the horizontal pipe.
Abstract:
Purpose
This study aims to present the numerical analysis of exergy transfer and irreversibility through the discrete filling of high-porosity aluminum metal foams inside the horizontal pipe.
Design/methodology/approach
In this study, the heater is embedded on the pipe’s circumference and is assigned with known heat input. To enhance the heat transfer, metal foam of 10 pores per inch with porosity 0.95 is filled into the pipe. In filling, two kinds of arrangements are made, in the first arrangement, the metal foam is filled adjacent to the inner wall of the pipe [Model (1)–(3)], and in the second arrangement, the foam is located at the center of the pipe [Models (4)–(6)]. So, six different models are examined in this research for a fluid velocity ranging from 0.7 to7 m/s under turbulent flow conditions. Darcy Extended Forchheimer is combined with local thermal non-equilibrium models for forecasting the flow and heat transfer features via metal foams.
Findings
The numerical methodology implemented in this study is confirmed by comparing the outcomes with the experimental outcomes accessible in the literature and found a fairly good agreement between them. The application of the second law of thermodynamics via metal foams is the novelty of current investigation. The evaluation of thermodynamic performance includes the parameters such as mean exergy-based Nusselt number (Nue), rate of irreversibility, irreversibility distribution ratio (IDR), merit function (MF) and non-dimensional exergy destruction (I*). In all the phases, Models (1)–(3) exhibit better performance than Models (4)–(6).
Practical implications
The present study helps to enhance the heat transfer performance with the introduction of metal foams and reveals the importance of available energy (exergy) in the system which helps in arriving at optimum design criteria for the thermal system.
Originality/value
The uniqueness of this study is to analyze the impact of discrete metal foam filling on exergy and irreversibility in a pipe under turbulent flow conditions.
References
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TL;DR: In this paper, numerical methods are used to solve the field equations for heat transfer in a porous medium filled with gas and bounded by plane rectangular surfaces at different temperatures, and the relative increases in heat transfer rate, corresponding to natural convection, are obtained as functions of 3-dimensional parameters: the Darcy number Da, the Rayleigh number Ra and a geometric aspect ratio L/D.
Abstract: Numerical methods are used to solve the field equations for heat transfer in a porous medium filled with gas and bounded by plane rectangular surfaces at different temperatures. The results are presented in terms of theoretical streamlines and isotherms. From these the relative increases in heat transfer rate, corresponding to natural convection, are obtained as functions of 3- dimensionless parameters: the Darcy number Da, the Rayleigh number Ra, and a geometric aspect ratio L/D. A possible correlation using the lumped parameter Da Ra is proposed for Da Ra greater than about 40. (33 refs.)
155 citations
TL;DR: In this article, a buoyancy-driven convection in a differentially heated vertical porous layer is studied theoretically by the method developed by Gill, where the model is of finite extent, and the temperature difference between the vertical walls is assumed to be large.
137 citations
TL;DR: In this paper, a simple analytical formula for calculating the heat transfer is presented, after obtaining a matching coefficient by comparison with numerical solutions, for both free and forced convection, simulating wall leakage in common building structures, are considered.
106 citations
TL;DR: In this paper, a numerical study of steady, natural convection in a fluid-saturated, horizontal, porous layer subjected to an end-to-end temperature difference was performed using a finite element computer program based on the Galerkin form of the finite element method.
Abstract: A numerical study of steady, natural convection in a fluid-saturated, horizontal, porous layer subjected to an end-to-end temperature difference is reported. The analysis is performed using a finite element computer program based on the Galerkin form of the finite element method. Heat transfer rates are predicted for aspect ratios ranging from 0.1 to 0.5 and Rayleigh numbers in the range 25 to 200. Representative plots of temperature and velocity fields are presented. Comparisons are made with an approximate analytical solution and regions of validity are identified for the analytical solution.
64 citations