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Combined gas radiation and laminar forced convection flow adjacent to a forward facing step in a duct

A.B. Ansari (Department of Mechanical Engineering, Shahid Bahonar University of Kerman, Kerman, Iran)
S.A. Gandjalikhan Nassab (Department of Mechanical Engineering, Shahid Bahonar University of Kerman, Kerman, Iran)

International Journal of Numerical Methods for Heat & Fluid Flow

ISSN: 0961-5539

Article publication date: 22 March 2013

158

Abstract

Purpose

The purpose of this paper is to focus on thermal characteristics behavior of forced convection flow in a duct over forward facing step (FFS), in which all of the heat transfer mechanisms, including convection, conduction and radiation, take place simultaneously in the fluid flow.

Design/methodology/approach

The fluid is treated as a gray, absorbing, emitting and scattering medium. The Navier‐Stokes and energy equations are solved numerically by computational fluid dynamics (CFD) techniques to obtain the velocity and temperature fields. Discretized forms of these equations are obtained by the finite volume method and solved using the SIMPLE algorithm. Since the gas is considered as a radiating medium, all of the convection, conduction and radiation heat transfer take place simultaneously in the gas flow. For computation of the radiative term in the gas energy equation, the radiative transfer equation (RTE) is solved numerically by the discrete ordinate method (DOM) to find the radiative heat flux distribution inside the radiating medium. By this numerical approach, the velocity, pressure and temperature fields are calculated.

Findings

The effect of wall emissivity, optical thickness, albedo coefficient and the radiation‐conduction parameter on heat transfer behavior of the system are also investigated. The numerical results for two cases of convection‐conduction and conduction‐radiation problems are compared with the available data published in open literature and good agreement was obtained.

Originality/value

This is the first time in which flow over FFS in a duct, considering all heat transfer mechanisms including conduction, convection and radiation, is solved numerically.

Keywords

Citation

Ansari, A.B. and Gandjalikhan Nassab, S.A. (2013), "Combined gas radiation and laminar forced convection flow adjacent to a forward facing step in a duct", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 23 No. 2, pp. 320-335. https://doi.org/10.1108/09615531311293498

Publisher

:

Emerald Group Publishing Limited

Copyright © 2013, Emerald Group Publishing Limited

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