Numerical Investigation of Sand Erosion Phenomena in Transonic Fan of Jet Engine

砂蚀是固体颗粒撞击管壁造成管壁表面严重机械损伤的现象。该现象是典型的气固两相湍流，可以看作是流场、粒子轨迹和壁面变形相互作用的多物理场问题。另一方面，在颗粒环境中工作的飞机发动机由于沙蚀而遭受性能和寿命的下降。因此，在研制中必须证明，当发动机吸入一定量的沙子时，发动机可以无故障地运行。在本研究中，我们将三维沙蚀预测程序应用于跨音速扇，并阐明了其物理机制。2008年，我们模拟并验证了粒子在激波中的运动，这种运动通常出现在跨音速风扇叶片通道中。2009年，我们新开发了风机三维转子/定子相互作用场的沙蚀预测代码。采用NASA转子37作为代码验证的目标。2011年，将规范应用于风机叶片的不同工况。通过对数值结果的分析，阐明了叶片的流动变化、叶片上的沙蚀现象、侵蚀叶片的几何形状和性能下降。

Sand erosion is a phenomenon whereby solid particles impinging on a wall cause serious mechanical damage to the wall surface. This phenomenon is a typical gas-solid two-phase turbulent flow and can be considered as a multi-physics problem in which the flow field, particle trajectory, and wall deformation interact. On the other hand, aircraft engines operating in a particulate environment are subjected to the performance and lifetime deterioration due to sand erosion. Therefore, in the development it must be proved that the engine can operate without any trouble when a certain amount of sand is sucked in the engine. In the present study, we apply our three dimensional sand erosion prediction code to a transonic fan, and clarify the physical mechanism. In 2008, a particle motion through a shock wave, which generally appears in a transonic fan blade passage, was modeled and verified. In 2009, we newly developed a sand erosion prediction code for a three-dimensional rotor/stator interaction field of a fan. NASA Rotor 37 was adopted as the target of the code verification. In 2011, the code was applied to different operating conditions of fan blade. Investigating the numerical results, the flow change, the sand erosion phenomena on the blade, the eroded blade geometry and the performance deterioration were clarified.