The vortex cooling mechanism under rotating conditions is researched by solving 3D steady Reynolds averaged Navier-Stokes equations coupled with the standard k-omega turbulence model. Grid independence analysis is performed to confirm the suitable mesh number for numerical simulation. Effects of rotation number, rotating direction and density ratio on vortex cooling flow and heat transfer behavior under rotating conditions are discussed in detail. Results show that rotation has a pronounced effect on vortex cooling characteristics. When the rotation number increases, the cooling air velocity decreases and pressure drop increases, leading to the decreasing heat transfer intensity. As the cooling air velocity and streamline are not very sensitive to rotating direction, slightly higher heat transfer intensity and more uniform Nusselt number distribution at Ro = 0.384 can be observed. The cooling air streamline almost stays unchanged and air velocity increases slightly with increasing density ratio. An increase in density ratio results in the increasing vortex heat transfer intensity. (C) 2016 Elsevier Ltd. All rights reserved.