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The research focuses on the high-load compressor cascade with a four-tooth straight-tooth labyrinth seal. Jet holes with varying air inlet and jet positions are designed to investigate the mechanism and principles underlying the impact of adaptive jets on the performance of compressor cascades. The results show that the jet flow from the labyrinth seal to the suction side has a good improvement effect on the performance of the compressor cascade, which can suppress the influence region of the concentrated separation vortex and the wall vortex, improve the flow field structure, reduce the total pressure loss, and enhance the expansion capacity. What is more, the improvement effect on the flow field structure and the performance is enhanced as the flow rate of the jet hole increases. The most significant improvement in the performance of the compressor cascade is achieved by introducing air from the second tooth cavity, which can reduce the total pressure loss coefficient by 3%, reduce the volume of low kinetic energy fluid clusters by 9.48%, and significantly enhance the performance of the compressor cascade. [ABSTRACT FROM AUTHOR]

In order to study the oil-gas two-phase flow characteristics in the bearing chamber of an aeroengine and improve the oil return effect of lubricating oil,an embedded improvement scheme was proposed for the ventilation structure of the bearing chamber.A two-phase flow solution model for the bearing chamber based on the Euler-Euler method was established,and the flow characteristics and oil return characteristics of conventional bearing chamber and embedded improvement bearing chamber under different operating conditions were analyzed.The results show that after the embedded improvement of the ventilation structure of the conventional bearing chamber,the lubricating oil is blocked by the embedded ventilation wall.Under the action of air shear force and gravity, the lubricating oil on the right side of the ventilation port moves downstream through the ventilation port,reducing the amount of lubricating oil flowing out of the ventilation port and increasing the amount of lubricating oil flowing out of the return port,thus significantly improving the return oil efficiency .As the embedding depth increases, the lubricating oil flowing out of the vent is further suppressed, the volume fraction of the lubricating oil in the chamber further increases,and the return oil efficiency is further improved.Compared with conventional bearing cavities,when the oil flow rate is 200 L/h and the rotation speed is 15 000 r/min,the embedded improvement scheme has the most significant improvement in oil return efficiency,and the oil return efficiency is increased by 16.72%, 18.80%, and 20.19% respectively for the improved schemes with embedded depths of 8 mm, 10 mm,and 12 mm. [ABSTRACT FROM AUTHOR]

In this paper, based on the airflow improvement mechanism of dragonfly wing veins, a vortex generator is designed at the leading edge of the suction surface to improve the flow condition of compressor cascades. The influence of the placement positions and geometric dimensions of the vortex generators on the flow field structure and aerodynamic performance is investigated by numerical simulation. The research reveals that vortex generators at the leading edge of the suction surface can generate induced vortices near the end wall, suppressing the accumulation of low-energy fluid in the corner region. This results in a backward shift of the separation initiation point, a reduction in the corner separation region along the pitch direction, and a reduction in flow loss. The vortex generators exhibit favorable characteristics with positive incidence angles. However, when the incidence angle is below the minimum loss incidence angle, the vortex generators increase the flow losses of the cascade. Optimum performance is achieved when the vortex generators are positioned at the start of the corner separation. The flow control influence initially increases and then decreases as the height of the vortex generators increases. Similarly, the control impact is enhanced and then weakened as the placement position moves away from the suction surface. The flow losses decrease by 10.3% when the vortex generators are placed at the junction between the end wall recirculation and the mainstream region at a height equal to 2% of the blade height. [ABSTRACT FROM AUTHOR]