Mixed convection heat transfer in a radially rotatingsquare duct with radiation effects

Abstract

The interaction of thermal radiation with laminar mixed convection for a gray fluid ina radially rotating square duct is numerically studied. The integro-differential radiative transferequation is solved by the discrete ordinates method. The coupled momentum and energyequations are solved by the DuFort–Frankel numerical scheme. Results are presented in a radiallyrotating square duct over a wide range of the governing parameters. The effects ofrotation-induced buoyancy and thermal radiation on the developments of velocity, temperature,friction factor and Nusselt number are examined in detail. The axial variations of the fReand Nu are characterized by a decay near the entrance due to the entrance effect, but thedecay is attenuated by the onset of the secondary flow. The predictions also demonstrate that theradiation presents significant effects on the axial distributions of the total Nusselt number Nu t and tends to reduce the centrifugal buoyancy effects. In addition, the heattransfer rate increases with the decrease in the conduction-to-radiation parameter N c.