Leakage Flow in Honeycomb-Labyrinth Seal Cavity in Stator of Low-Speed Research Compressor

The honeycomb at the inner band of a compressor stator and the labyrinth on the disk form a sealed cavity, in which the clearance leakage flow has a key impact on the aerodynamic performance of the axial flow compressor. In this paper, focusing on the first 1.5-stage of a low-speed research compressor, numerical simulations are conducted to compare the impact of honeycomb seal structure and slide wall on the aerodynamic performance of the compressor, as well as the performance changes of honeycomb seal structure under two different labyrinth seal clearance conditions. The performance calculation results show that the isentropic efficiency of the compressor equipped with the 0.2-mm-clearance honeycomb cavity model is slightly lower than that of the slide-wall cavity model, which is attributed to the elevated total temperature rise induced by the leakage flow inside the cavity. Comparative analysis of cavity leakage flow characteristics and detailed flow field investigation indicate that honeycomb structure induces a simultaneous increase in both the cavity leakage flow rate and swirl angle. A strong interaction is observed between the airflow within the cavity and the honeycomb structure, creating a complex vortex flow that significantly elevates the total temperature in both the seal cavity and the honeycomb itself. This temperature elevation ultimately leads to a reduction in compressor efficiency. In contrast, when the zero-clearance honeycomb model is compared with the 0.2-mm-clearance honeycomb model, the decreased total temperature ratio contributes to an improvement in isentropic efficiency. In the zero-clearance model, although the average total temperature of the leakage flow rises owing to the reduced clearance, the compressor efficiency is enhanced by the substantial reduction in leakage flow rate. The findings in this paper clarify the quantitative relationship and influence mechanism of leakage flow under different clearance conditions on the performance of the honeycomb and labyrinth seal structure applied to the compressor stator, which therefore provide certain references for the engineering design of honeycomb seal cavities.