机匣转静刮磨后轴流压气机气动性能评估研究

Aerodynamic Performance Evaluation under Rotor and Shroud Scraping of Axial Compressor

关键词:  机匣磨损  叶尖间隙  壁面粗糙度  激波  流动分离

Key words:  Shroud wear  Tip clearance  Wall roughness  Shock wave  Flow separation

摘要:

为揭示机匣可磨耗涂层磨损造成的叶尖间隙和粗糙度变化对压气机气动性能的影响规律，针对不同刮磨形貌下Rotor 37转子性能进行了数值模拟研究。结果表明，压气机等熵效率和出口流量对刮磨间隙和粗糙度的变化较为敏感，降幅最高可达1.78%和0.83%，而压比变化不大；刮磨间隙深度增加，刮磨最深位置前移时，叶尖泄漏增强，泄漏流与上端壁附面层及主流相互作用演变为泄漏涡，与激波相互干涉，造成较大的叶尖损失；压气机气动性能受磨损区域粗糙度影响较小，虽然等熵效率对粗糙度变化较为敏感，但最大降幅也仅为0.38%。磨损区域粗糙度增加时，近壁区湍流波动加强且气流更易分离，引起叶尖泄漏流和叶片尾迹区域的流动结构变化，使压气机气动特性向低流量方向偏移。

Abstract:

The wear of the abradable coating on the casing will increase the tip clearance and roughness. In order to reveal the impact mechanism of compressor aerodynamic performance degradation caused by coating wear， the numerical simulation was conducted on the Rotor 37 of the casing with different scraping conditions. The results show that the isentropic efficiency and outlet flow rate of the compressor decrease with the increase of the scraping gap and roughness， and the decrease can reach up to 1.78% and 0.83%， while the pressure ratio is almost unchanged. When the wear gap increases and the deepest position of the scraping is moved forward， a stronger tip leakage vortex will be formed by the interaction between the leakage and the main stream and the boundary layer flow of the shroud wall， which will interfere with the shock wave and cause greater tip loss. When the roughness of the wear area increases， there is no significant compressor performance degradation. The isentropic efficiency is more sensitive to the roughness changes， but the maximum decrease is only 0.38%. When the roughness of the wear area increases， the turbulent fluctuations in the near wall area are strengthened and the air flow separation is easier， which causes the flow structure change of the leakage flow and the blade wake area， and makes the aerodynamic characteristics of the compressor shift to the direction of low flow.