Nonuniform Leakage Characteristics of Straight‐Through Labyrinth Seal Under Large Driving Pressure Ratio

The straight‐through labyrinth seal is a noncontact sealing component that is widely applied in aeroengines. The leakage characteristics may be affected by the uneven distribution of the clearance height caused by eccentricity and deflection. In this study, numerical simulation was used to analyze the influence of the clearance height, eccentricity, and deflection angle on the leakage characteristics under a large driving pressure ratio. The accuracy of the numerical simulation method was verified using the well‐known labyrinth seal experimental results. The results show that with an increase in pressure ratio, the converted flow rate increased linearly, and the growth gradually slowed. As the pressure ratio increases further, the labyrinth seal reaches a critical state, and the converted flow rate tends to stabilize. Simultaneously, the turbulent kinetic energy at the outlet increases sharply. The critical state is determined by the pressure ratio and the clearance height. The influence of eccentricity on the leakage was equivalent to changing the average clearance height of the labyrinth seal. Deflection significantly reduces the converted flow rate. Moreover, an empirical equation for the converted flow rate is established. The error between the calculated value and typical experimental value is approximately 1% when π ≥ 3.