The axial compressor in compressed air energy storage (CAES) system needs to operate stably and efficiently within a wide working range. The stator gap plays a critical role in suppressing corner separation and enhancing blade throughflow. The primary objective of this study is to determine the optimal combination of stator gaps to further expand the stable working range of the compressor while ensuring high efficiency. In this study, the flow characteristics of different stator gaps of the five-stage axial compressor in a specific CAES system are researched numerically. Firstly, the impact of different stator gaps on the aerodynamic performance is analyzed. The stator gap effectively broadens the stable working range of the compressor, with the hub gap exhibiting greater potential for expansion compared to the shroud gap. Subsequently, a comparative analysis is conducted on the internal flow of the third stage stator under near-stall conditions. Different gap leakage forms different vortex structures, and the gap leakage can effectively eliminate the accumulation of low-energy fluid in the corner area, optimize the limit streamlines on the blade suction surface and the temperature distribution. The low-velocity area caused by different stator gaps is also different. Finally, energy loss and energy dissipation with different stator gaps are explored. The gap leakage flow results in high energy loss, and different stator gaps exhibit notable differences in distribution of the high energy loss regions. Different types of stator gaps exhibit consistent high energy dissipation areas, which include the leading-edge stagnation area, boundary layer area on blade surface, and wake area. It is important to note that the high energy loss area does not necessarily coincide with the high energy dissipation area. The combined application of two loss evaluation methods contributes to a more comprehensive investigation of the loss distribution characteristics of the compressor.

中文翻译：

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压缩空气储能系统中不同定子间隙轴流压缩机特性

压缩空气储能（CAES）系统中的轴流压缩机需要在较宽的工作范围内稳定、高效地运行。定子间隙在抑制角分离和增强叶片通流方面起着至关重要的作用。本研究的主要目的是确定定子间隙的最佳组合，以进一步扩大压缩机的稳定工作范围，同时确保高效率。本研究对特定CAES系统中五级轴流压缩机不同定子间隙的流动特性进行了数值研究。首先分析了不同定子间隙对气动性能的影响。定子间隙有效地拓宽了压缩机的稳定工作范围，与护罩间隙相比，轮毂间隙表现出更大的扩展潜力。随后对近失速工况下第三级定子内部流动进行了对比分析。不同的间隙泄漏形成不同的涡流结构，间隙泄漏可以有效消除角部区域低能流体的积聚，优化叶片吸力面的极限流线和温度分布。不同的定子间隙引起的低速区也不同。最后，探讨了不同定子间隙下的能量损失和能量耗散。间隙漏流导致高能量损失，不同定子间隙的高能量损失区域分布存在显着差异。不同类型的定子间隙表现出一致的高耗能区域，包括前缘停滞区域、叶片表面边界层区域和尾流区域。需要注意的是，高能量损失区域不一定与高能量耗散区域重合。两种损失评估方法的结合应用有助于更全面地研究压缩机的损失分布特性。