Due to the impact of various environmental factors during operation, the surface roughness of aero engine compressor blades deteriorates to varying degrees. This degradation adversely affects both the aerodynamic performance and the stability of the compressor. In this study, the commercial software CFX was used to numerically simulate the Darmstadt Transonic Compressor (DTC), representing the operating conditions of the first stage of a high-pressure compressor. The transition gamma-theta model and roughness correction were applied. The surface roughness variation was modeled for individual blade rows and all three rows of the outlet guide vane (OGV), first-stage rotor (R1), and first-stage stator (S1), with the leading edge area modeled separately based on the actual roughness distribution of the blades. The results indicate that an increase in surface roughness leads to a reduction in the compressor’s total pressure ratio and efficiency, as well as a narrowing of the stable operating range. The rough rotor with Ra of 5μm and 20μm caused 0.78% and 4.10% reduction in peak efficiency. At the peak efficiency (PE) and the near stall (NS) conditions, the mechanisms behind performance degradation due to rough blades differ. At the PE condition, the rough surface promotes early flow separation on the rotor suction side, increasing losses due to blade wake flow. Roughness on the rotor, especially near the leading edge (5%-10% chord), significantly affects the flow field near the blade surface, in contrast to the stator. However, at the NS condition, the primary factor contributing to performance degradation is an increase in rotor tip leakage flow, while the roughness has minimal impact on the flow field near the blade surfaces. Moreover, the decrease in total pressure ratio and efficiency shows varying sensitivity to rotor and stator roughness.
Lai et al. (Sat,) studied this question.
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