Influence of Tooth Position and Clearances on Leakage in Labyrinth Seal in Turbine

The labyrinth seal belongs to the category of complex structure labyrinth seal, which is widely applied in engineering for its better leakage control due to its multiple throttle mechanism which guarantees a more satisfactory energy dissipation. By using Fluent, the flow and the leakage in labyrinth seal were predicted by employing two-dimensional steady flow model, the κ-ε turbulence model and numerically solving the Navier-Stokes equations. The leakage rates to rotor axial shifting were compared between Fluent and Perturbation, and the largest difference was less than 5%. The flow and the leakage in labyrinth seals were compared over a range of seal clearances and short tooth axial positions at the same pressure ratio. It was detected that the leakage rate increased linearly with seal clearance, and the perfect labyrinth seal structure to control leakage was also found. The influence of the pressure ratio on leakage rate was investigated, and it was detected that the leakage rate increased linearly with pressure ratio. The study lays the theoretical foundation for the optimization design of the labyrinth seal.