Analysis of flow and heat transfer in porous media imbedded inside various-shaped ducts

Applied Thermal Engineering

2009

Applying a Fourier series approach, closed form solutions for fully developed velocity and temperature distribution in a porous-saturated microduct of rectangular cross-section are presented in the slip-flow regime. The Brinkman flow model is applied. Invoking the temperature jump equation, the H1 thermal boundary condition is investigated. Expressions are presented for the local and average velocity and temperature profiles, the friction factor, and the slip coefficient in terms of the key parameters. The present results, which are applicable to microducts of rectangular cross-section filled with or without a porous medium, are found to be in complete agreement with those available in the literature for both no-slip and slip flow regime.

Section: Introductionmentioning

confidence: 99%

Slip flow forced convection in a microporous duct of rectangular cross-section

Applied Thermal Engineering

2009

“…The method of weighted residuals was exploited by Haji-Sheikh and Vafai [4] in their study of thermally developing convection in ducts of various shapes. In a subsequent study, HajiSheikh [5] has applied a Fourier series method to investigate fully developed forced convection in a duct of rectangular cross section.…”

Section: Introductionmentioning

confidence: 99%

Heat transfer and entropy generation optimization of forced convection in porous-saturated ducts of rectangular cross-section

International Journal of Heat and Mass Transfer

Gurgenci

Merrikh

2007

We investigate analytically the First and the Second Law (of Thermodynamics) characteristics of fully developed forced convection inside a porous-saturated duct of rectangular cross-section. The Darcy-Brinkman flow model is employed. Three different types of thermal boundary conditions are examined. Expressions are presented for the Nusselt number, the Bejan number, and the dimensionless entropy generation rate in terms of the system parameters. The conclusion of this analytical study will make it possible to compare and evaluate alternative rectangular duct design options in terms of heat transfer, pressure drop, and entropy generation.

“…A substantial amount of literature on this topic is available (see, for example, the surveys in Nield and Bejan [3], Lauriat and Ghafir [4] and, for early work, Haji-Sheikh and Vafai [5]). For circular ducts or parallel plate channels the simplicity of the geometry allows analytical solutions of closed form.…”

Section: Introductionmentioning

confidence: 99%

“…This method was exploited by Haji-Sheikh and Vafai [5] in their study of thermally developing convection (the Graetz problem) in ducts of various shapes, including elliptical ones. This method is especially convenient when the boundary conditions are homogeneous, as in the forced convection problem with uniform temperature imposed on the walls.…”

Section: Introductionmentioning

confidence: 99%

Effects of temperature-dependent viscosity variation on entropy generation, heat and fluid flow through a porous-saturated duct of rectangular cross-section

Gurgenci

2007

Appl Math Mech

Effect of temperature-dependent viscosity on fully developed forced convection in a duct of rectangular cross-section occupied by a fluid-saturated porous medium is investigated analytically.The Darcy flow model is applied and the viscosity-temperature relation is assumed to be an inverse-linear one. The case of uniform heat flux on the walls, i.e. the H boundary condition in the terminology of Kays and Crawford [1], is treated. For the case of a fluid whose viscosity decreases with temperature, it is found that the effect of the variation is to increase the Nusselt number for heated walls. Having found the velocity and the temperature distribution, the second law of thermodynamics is invoked to find the local and average entropy generation rate.Expressions for the entropy generation rate, the Bejan number, the heat transfer irreversibility, and the fluid flow irreversibility are presented in terms of the Brinkman number, the Péclet number, the viscosity variation number, the dimensionless wall heat flux, and the aspect ratio (width to height ratio). These expressions let a parametric study of the problem based on which it is observed that the entropy generated due to flow in a duct of square cross-section is more than those of rectangular counterparts while increasing the aspect ratio decreases the entropy generation rate similar to what previously reported for the clear flow case [2].