Forced convection of radiating gas over an inclined backward facing step using the blocked-off method

Abstract

The present work investigates the laminar forced convection flow of a radiating gas over an inclined backward facing step in a horizontal duct. The momentum and energy equations are solved numerically by the computational fluid dynamics techniques to obtain the velocity and temperature fields. Since, the 2-D Cartesian co-ordinate system is used to solve the governing equations; the flow over inclined surface is simulated by considering the blocked-off region in regular grid. Discretized forms of the governing equations in the (x,y) plane are obtained by the control volume method and solved using the SIMPLE algorithm. The fluid is treated as a gray, absorbing, emitting, and scattering medium. Therefore, all of the convection, conduction and radiation heat transfer mechanisms take place simultaneously in the gas flow. For computation of the radiative term in the gas energy equation, the radiative transfer equation is solved numerically by the discrete ordinates method to find the radiative heat flux distribution inside the radiating medium. In the numerical results, effects of inclination angle, optical thickness, scattering albedo and the radiation-conduction parameter on the heat transfer behavior of the convection flow are investigated. This research work is a new one in which a combined convection-radiation thermal system with a complex flow geometry is simulate by efficient numerical techniques.