EFFECTS OF WALL TRANSPIRATION ON MIXED CONVECTION IN A RADIAL OUTWARDFLOW INSIDE ROTATING DUCTS

The present work treats the transport phenomena in a radial-outward fl ow inside rotating ducts with rotation-induced buoyancy and wall trans piration effects. Using the vorticity-velocity method, the three-dimen sional Navier-Stokes equations and the energy equation were solved sim ultaneously. Predicted results are presented for air flowing in a rect angular duct over-a wide range of governing parameters. In this work, both the thermal boundary conditions of uniform wall temperature (UWT) and-uniform heat flux (UHF) are considered. The results disclose that the axial variations of the peripherally averaged friction factor and Nusselt number are closely related to the emergence, disappearance, g rowth and decay of the rotation-induced secondary vortices. The Nu is enhanced with an increase in the rotation number Ro. Predicted results also show that near the entrance, the fRe increases with an increase in the wall Reynolds number Re-w. But as the flow goes downstream, the fRe decreases With Re-w. Additionally, the fRe and Nu for the UWT cas e are lower than those for the UHF case near the inlet but surpass the m downstream.