The Sealing Efficiency and Interaction between Purge Flow and Mainstream Flow for Novel Rim Seal Configurations

Abstract

The rim seal is used to prevent the mainstream ingestion to the gap between the turbine vane and blade. In this research, the dolphin lip with a hook configuration and a large seal cavity with hook structures are designed based on the high-pressure turbine datum single shark lip rim seal configuration. Sealing effect and flow field parameters are measured by the experiment method, and numerical simulation is used to supplement the mechanism. For three configurations, the effect of leakage slot vortex on seal efficiency and the influence of leakage vortex generated by the interaction between purge flow and mainstream are discussed in depth.The results show that the dolphin lip with hook structure form a reverse vortex which contrary to the leakage slot vortex to increase the sealing efficiency, and the large seal cavity makes the sealing efficiency is higher than the datum structure. With different purge flow rates and unequal seal structures, purge flow produces three types of leakage vortexes in the passage. Besides, the seal configuration with dolphin lip will produce Kelvin-Helmholtz instability at the interface between the purge flow and mainstream at a lower purge flow rate, and thus induce new leakage vortex branches in the blade passage.