The Impact of Seal Clearance on Sealing Performance in the Single-Wall-Hole Honeycomb Seal

The structural parameters of the honeycomb seal (HCS) significantly affect its leakage characteristics. We previously introduced an innovative honeycomb seal, the single-wall-hole honeycomb seal (S-WHHCS), featuring enhanced sealing performance. To delve into the influence of the structural parameters, the leakage characteristics of S-WHHCS are investigated via the computational fluid dynamics (CFD) method. The sealing performance of S-WHHCS under different seal clearances and operating conditions is studied. The results show that the leakage reduction rate of the S-WHHCS relative to the HCS decreases by at least 54.81% when the clearance increases from 0.2 mm to 0.5 mm. As the rotational speed rises, the effect of wall holes on sealing performance becomes less significant. When the clearance is 0.5 mm, the minimum velocity beneath cavity number 7 is 35.4% higher than when the clearance is 0.2 mm, and the fluid in the clearance is predominantly dominated by high-speed flow. The leakage reduction effect of the honeycomb cavities diminishes as the sealing gap increases. Specifically, the vortex dissipation effect of honeycomb cavities with an axial hole number of 14 is reduced by 72.3% when the clearance increases from 0.2 mm to 0.5 mm. As the sealing gap widened, both the vortex dissipation effect in the honeycomb cavities and the throttling effect decreased, leading to a decrease in sealing performance. At the same time, the significance of wall holes in the overall sealing system diminishes as the leakage reduction effect of the honeycomb structure decreases. The increase in the sealing gap diminishes the leakage reduction effectiveness of the honeycomb cavities and wall holes, resulting in a decrease in sealing performance.