Review on internal flow mechanism and control methods of axial flow compressor at low Reynolds number

With the continuous increase of aeroengine flight ceiling (>20 km), the thin atmosphere at high altitudes and the size effect all cause the compressor component inlet Reynolds number to decrease rapidly to a critical value (approximately 2.0 × 10⁵), and the significant transition process on the blade/endwall surface leads to the sharp degradation of compressor performance, which seriously affects the engine fuel consumption and working stability at high altitudes. In this paper, the research progress on the internal flow mechanism and flow control methods of axial compressors at low Reynolds numbers is reviewed from the aspects of quantification and prediction of performance variation, flow loss mechanism related to separation and transition, efficient transition control and flow field organization. The development trend of the low-Reynolds-number effect of axial flow compressors is noted, and the difficulties and application prospects of aerodynamic design and efficient flow control methods for compressors under low Reynolds numbers at high altitudes are discussed.