Dynamic coupling evolution mechanism of shock waves and boundary layers in transonic compressor stall inception and its numerical study

Spike-type stall inception remains a critical challenge for the stable operation of high-speed transonic compressors due to its abrupt emergence and rapid nonlinear evolution. The primary objective of this study is to elucidate the underlying physical mechanisms driving the rapid growth of spike-type disturbances by establishing a quantitative theoretical model based on a positive feedback loop. This model focuses on the intricate coupling between passage flow blockage, shock-wave/boundary-layer interaction (SWBLI), and the resulting shock-front instability at the blade tip. By analyzing the trajectory of the disturbance evolution, we identify a distinct “rapid amplification stage” that serves as the core of the stall inception process. The results demonstrate a significant demarcation in timescales: while the global evolution from the first localized velocity deficit to a fully developed stall cell typically spans three to five rotor revolutions, the most critical phase of rapid growth, defined between the onset of blockage surge at Point C and the peak growth rate at Point D, is completed within approximately 1.3 revolutions. During this concentrated window, the positive feedback mechanism triggers an exponential-like increase in blockage, providing a rigorous physical explanation for the sudden “jump” observed in experimental stall precursors. These findings not only clarify the temporal dynamics of spike-type stall but also provide a theoretical framework for improving the precision of stall warning systems and the effectiveness of active stability control in advanced compression systems.