Abstract: In order to investigate the flow and heat transfer performances in a pre-swirl rotor-stator cavity with two air inflows (central air inflow and pre-swirl inflow at stator rim respectively) and two outflows (radial outflow at ourter shroud and axial outflow at rotor rim respectively),a numerical study is conducted by using RNG turbulent model.In the cavity,there are stator septa and rotor septa dividing the inner rotor-stator cavity from the outer pre-swirl cavity.Because of the periodic feature of the flow structure,one thirtieth of the cavity is considered as the computational field.The results show that the rotating Reynolds number,non-dimensional flow velocities,and pre-swirl ratio have different effects on the flow and heat transfer characteristics in the rotor-stator cavity.The synergism of pre-swirl and septa makes satisfactory shroud seals preventing the ingress of hot gas from flowing into the inner rotor-stator cavity and providing the cooling air flowing into blade-cooling holes.