Numerical Clarification of Wavy Sand Erosion Phenomena generated by Interaction among Flow, Small Particle and Wall Surface

砂蚀是一种固体颗粒撞击壁面造成壁面严重机械损伤的现象。这是一个典型的多物理场问题，其中流场，颗粒轨迹和壁面变形等相互作用。众所周知，各种机器的性能和寿命由于沙侵蚀而严重降低。我们开发了数值程序的沙侵蚀现象。为了模拟这一现象，反复计算了湍流流动、颗粒运动轨迹和冲蚀壁面上的冲蚀量。本文采用Neilson-Gilchrist模型计算沙侵蚀引起的重量损失，并在2004年将该模型扩展到三维计算，将其应用于90 °弯曲。其主要目的是澄清波浪形侵蚀模式形成的弯曲壁的原因。计算了9个不同粒径和壁曲率的病例。墙的材料 ...更多信息 颗粒分别采用铝和碳化硅。结果表明：（1）颗粒与壁面碰撞后，壁面上会产生冲蚀空洞;（2）冲蚀空穴主要沿流向生长，（3）冲蚀空穴沿展向生长受弯曲壁面纵向垂直运动的控制，（4）上述现象导致弯曲壁面上的波浪形冲蚀。首先，将代码扩展到旋转参考系。在所有计算中使用了大约300万个网格点。结果表明：（A）在转子压力侧的前缘和叶尖附近发生严重的砂蚀;（B）由于动能较小，在定子中未出现明显的砂蚀;（C）在转子通道中，离心力使颗粒向叶尖移动;（D）颗粒在定子中加速，因此在下游级中将再次发生砂蚀。然而，由于波浪形侵蚀模式没有清楚地再现，将需要进一步的调查。少

Sand erosion is a phenomenon where solid particles impinging to a wall cause serious mechanical damages to the wall surface. This phenomenon is a typical multi-physics problem where the flow field, particle trajectory and wall deformation interact with among others. It is well known that the performance and lifetime of various machines are severely degraded due to sand erosion. We have developed the numerical procedure for sand erosion phenomenon. To simulate the phenomenon, the turbulent flow, the particle trajectory and the amount of erosion on the eroded wall were calculated repeatedly. The Neilson-Gilchrist model was used to estimate the weight loss due to sand erosion.In 2004, we extended this code to a three-dimensional computation, and it was applied to the 90-degree bend. The main objective was to clarify the reason why the wavy erosion pattern is formed over the curved wall. 9 cases with different particle diameters and wall curvatures were computed. The materials for the wall … More and the particle were adopted as aluminum and silicon carbide, respectively. It was found that (1)once a particle hits against a wall, an erosion cavity is generates on the wal,. (2)the erosion cavity mainly grows in the streamwise direction, (3)the spanwise growth of the erosion cavity is dominated by the longitudinal vertical motion over the curved wall, and (4)the above described phenomena produces the wavy erosion pattern over the curved wall.In 2005, I tried to clarify the mechanism of wavy sand erosion in a compressor blade passages. First, the code was extended to the rotational frame of reference. About 3 million grid points were used in all computations. It was confirmed that (A)sand erosion severely occurs around the leading edge and the tip of the rotor pressure side, (B)erosion does not appear remarkably in the stator because of the less kinetic energy, (C)in the rotor passage the centrifugal force makes the particles go toward the tip, and (D)particles are accelerated in the stator and thus sand erosion would take place again in the downstream stages. However, since wavy erosion pattern has not clearly reproduced, further investigations will be needed. Less