Numerical Investigaton of Sand Erosion Phenomena in Rotor/Stator Interaction of Jet Engine Compressor

砂蚀是固体颗粒撞击壁面造成壁面严重机械损伤的现象。众所周知，飞机、船舶、燃气轮机、泵等各种机器的性能和寿命都因沙蚀而严重退化。这种现象是典型的气相两相湍流，是流场、粒子轨迹和壁面变形相互作用的多物理场问题。然而，传统的模拟并未考虑侵蚀过程中流场及相关颗粒轨迹的变化。这种治疗在生理上是不现实的。因此，我们开发了沙蚀现象的数值计算程序，包括流场和壁面形状的时间变化。在本研究中，我开发了一个代码来模拟轴向压气机转子/定子相互作用中的沙蚀现象，以澄清物理和对气动性能的影响。在2006年，我扩展了我们现有的旋转参照系代码来计算转子/定子相互作用。然后，将该规范应用于一个90度弯曲的方形截面，其中发生了砂石侵蚀。将数值计算结果与实验数据进行比较，证实所编制的程序能较好地再现湍流和侵蚀面随时间的变化。2007年，将该代码应用于某轴向压气机的转子/定子相互作用问题，以澄清其物理性质。通过对数值结果的分析，证实了第一次撞击导致转子前缘周围的冲蚀最为严重，转子尾缘尖端附近的冲蚀较为严重，因为离心力使大量颗粒向该区域移动。

Sand erosion is a phenomenon where solid particles impinging to a wall cause serious mechanical damages to the wall surface. It is well-known that the performance and lifetime of various machines, such as airplane, ship, gas turbine, pump and so on, are severely degraded due to sand erosion. This phenomenon is E typical gas-particle two-phase turbulent flow and a multi-physics problem where the flow field, particle trajectory and wall deformation interact with among others. However, the change of the flow field and the relating particle trajectory during the erosion process have not been taken into account by conventional simulations. This treatment is physically unrealistic. Hence, we have developed the numerical procedure for sand erosion phenomenon, including the temporal change of the flow field and the wall shape. In the present research, I developed a code to simulate sand erosion phenomena in a rotor/stator interaction of an axial compressor, in order to clarify the physics and the effects on the aerodynamic performance.In 2006, I extended our existing code for rotational frame of reference to compute a rotor/stator interaction. Then the code was applied to a 90-degree bend with a square cross-section in which sand erosion took place. Comparing the numerical results with the experimental data, it was confirmed that the developed code can reproduce the temporal changes of the turbulent flow and eroded surface satisfactorily.In 2007, the code was applied to a rotor/stator interaction problem of an axial compressor, to clarify the physics. Investigating the numerical results, it was confirmed that the first impact leads to the most severe erosion around the rotor leading edge, and relatively severe erosion occurs around the tip of the rotor trailing edge, because centrifugal force makes a number of particles go towards the region.