Abstract: In order to study the feasibility of the leaf seal replacing the labyrinth seal used in turbine stage, the labyrinth seal of the corresponding parts of one and a half high-pressure turbine stage is replaced by leaf seal, numerical simulation is carried on by using the commercial software CFX, and the result is compared with the original one and a half stage with labyrinth seal. The result shows that, although the simple seal replacement reduces the leakage flow of the seal, but does not reduce the leakage loss of turbine stage, and enhance the interference of the leakage flow to mainstream, the simple design is not feasible. So as to match the leaf seal, the balance hole and the axial gap reasonably, on the basis of the original design, the leaf seal is used as the stator diaphragm seal and the rotor tip seal, and the labyrinth seal is set in the axial gap of the turbine stage. To the final scheme of leaf seal applied to turbine stage, the leaf seal and balance hole achieve reasonable match, and improve the aerodynamic performance, reduce the leakage loss, provide a good inlet condition to the next turbine stage at the same time.

Key words: turbine stage;leaf seal;labyrinth seal;balance hole;leakage flow