Numerical Simulation on Flow Characteristic in Labyrinth Seal Passage

To investigate leakage characteristic of labyrinth seal of steam turbine for engineering design, the flow fields in straight and stepped labyrinth seal passages are numerically simulated by computational fluid dynamics(CFD) method in different conditions and structural sizes and shapes. Subsequently, the flow characteristic in labyrinth seal is analyzed in detail. Simulation results show that the leakage can be effectively reduced by decreasing the pressure ratio, the clearance width, or the angle between axis and cavity edge, or by increasing the number of throttles, but the leakage is insensitive to the speed of rotor.