Extension of the Moore–Greitzer framework for accurate mathematical modelling of flow instabilities in a low-speed isolated axial compressor rotor blades row

Abstract

The mathematical models presented for describing flow instabilities in compressors rely on parameters that are not directly related to physical characteristics of machines, which may lead to inaccurate results. The most frequent model used for predicting flow instabilities in axial compressors is the Moore-Greitzer model; however, its predictive accuracy is strongly affected by the simplified representation of the performance characteristic. The present study offers modifications to this method through utilizing experimental performance curves and reconstructing it using a piecewise cubic polynomial formulation. Analysis of the B-Greitzer parameter for low-speed isolated axial compressor rotor blades row identifies a critical threshold at B = 0.71 marking transition between rotating stall and surge. As the B parameter increases, both the frequency and amplitude of flow oscillations are affected. The predictive capability of the original and modified models is assessed against experimental data. The proposed method significantly improves accuracy, reducing RMS errors from 11.97 to 0.89% for loading factor and from 5.65 to 0.81% for flow coefficient, providing a reliable and practical framework for real-world applications. Alongside ensured safety operation, this refined model has the potential of implementation in advanced control strategies, enabling compressors to operate more efficiently near the instability boundaries.