A new technique for controlling the tip leakage flow of micro turbine is presented.It uses backward vortex generators（BVGs）to control and reduce the tip leakage flow.The gas is driven by the pressure difference between pressure surface and blade tip,so it flows into BVGs from the pressure side of blade and flows out from the blade tip with high speed in the inverse-direction of leakage flow.Numerical simulations of typical turbine cascade in millimeter scale with and without BVGs are performed.The influence of BVGs on the flow fields and the performance of cascade is analyzed.The results show that the mass of leakage flow decreases by 2.8% and the circumferential load increases by 7.7% under typical entrance condition.Moreover,compared with the case without BVGs,the turbine efficiency grows about 1.2 % in case with BVGs.
