Study of Laminar Forced Convection of Radiating Gas Over an Inclined Backward Facing Step Under Bleeding Condition Using the Blocked-Off Method

Abstract

This paper presents a numerical investigation for laminar forced convection flow of a radiating gas over an inclined backward facing step in a horizontal duct subjected to bleeding condition. The fluid is treated as a gray, absorbing, emitting, and scattering medium. The two-dimensional Cartesian coordinate system is used to simulate flow over inclined surface by considering the blocked-off region in regular grid. The governing differential equations consisting the momentum and energy are solved numerically by the computational fluid dynamics 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, 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 ordinate method to find the radiative heat flux distribution inside the radiating medium. The effects of bleeding coefficient, inclination angle, optical thickness, albedo coefficient, and the radiation-conduction parameter on the flow and temperature distributions are carried out.

Numerical investigation of entropy generation in laminar forced convection flow over inclined backward and forward facing steps in a duct under bleeding condition

“…The effect of radiative parameters on thermal behavior of fluid flow was also studied. Ansari and Gandjalikhan Nassab [19] analyzed laminar forced convection flow of a radiating gas over an inclined backward facing step in a horizontal duct subjected to bleeding condition. The fluid was treated as a gray, absorbing, emitting and scattering medium.…”

Simulation of three-dimensional laminar forced convection flow of a radiating gas over an inclined backward-facing step in a duct under bleeding condition

“…The fixed inclination angle of È ¼ 45 is considered for BFS. In numerical calculations, the Reynolds number Ansari and Gandjalikhan nassab [17] Re = 400 RC = 50 ω = 0.5 τ = 0.005 Figure 6. Distribution of total Nusselt number along the duct for combined radiation-convection flow.…”

Inverse Convection–Radiation Boundary Design Problem of Recess Flow with Different Conditions

“…Chiu and Yan (2008) studied the effects of thermal buoyancy and the radiative transfer on the distributions of bulk fluid temperature, friction factor and Nusselt number in an inclined rectangular duct, while the radiative transfer equation was solved by the discrete ordinates method. Ansari and Nassab (2011) investigated several parameters such as the effects of radiation-conduction parameter, inclination angle, bleeding coefficient and optical thickness in laminar forced convection flow of a radiating gas over an inclined backward-facing step of a horizontal duct under bleeding condition. The foregoing studies are called direct method which means all of the boundary conditions and fluid flow properties are specified as input data to find medium temperature and wall heat flux distributions, whereas in inverse method, boundary conditions or fluid flow properties could be unknown and must be found.…”