Influence of inlet distortion on the wear of aero-compressor blades

Abstract

The turboshaft engine is the main power source of a helicopter. Under airborne conditions, inlet distortion inevitably occurs at the entrance of the compressor because of factors such as airflow and environmental turbulence. The change in the internal flow field alters the erosive wear law of compressor blades caused by sand particles. The influence of total pressure inlet distortion on the erosive wear of compressor blades is studied innovatively in this paper. A new parameterization method of the erosive wear model is proposed through particles velocity test and erosive wear experiment. The rotor blades of pre-1.5 stage compressor are used as the research object. A wear analysis model of the full-port compressor blades is established, which can take into account the inlet distortion. The influence mechanism of typical inlet distortion angles on the erosive wear distribution characteristics and wear degree of the rotor blades is revealed. The results show that inlet distortion significantly alters the wear characteristics of the rotor blades. Specifically, owing to the pressure difference and suction effect of the high-speed rotor blade, the sand particles in the distortion-affected area exhibit aggregation, re-aggregation, and transfer phenomena, which leads to considerable differences in the distribution characteristics and degree of the erosive wear between the rotor blades’ entering the distortion area and their exiting the distortion area. When the inlet distortion angle is expanded from 30° to 90°, compared with the rotor blade in the non-distortion-affected area, the wear degrees of the rotor blade affected by the inlet distortion increase by 32.5–68.7% at the leading edge and by 51.3–57% at the middle position. Moreover, when the inlet distortion angle increases, the maximum wear rate concentration values at the leading edge of the blade with the most serious wear and second most serious wear in the entire circumference of the rotor blade decrease by 4.26% and 27.3%, respectively.