Time resolved simulation of particle rebound for erosion calculation in jet aero engines

在目前的研究计划中，将研究在周围流体中运输的固体颗粒的冲击对材料的机械损伤，也称为侵蚀。目的是通过数值与实验相结合的方法改进涡轮航空发动机性能退化预测。侵蚀颗粒作为气流的一部分进入发动机的气路并损坏部件，特别是叶片。侵蚀的几何形状导致空气动力学的偏差，从而导致组件性能的恶化。组成部分的形状变化是由粒子的运动轨迹决定的。由于飞机发动机气体路径的复杂几何形状，这些侵蚀颗粒的确切轨迹很难预测。这些轨迹是由气动力决定的，但也由气体路径壁面或叶片上颗粒的反弹行为决定。现有的弹跳模型不够精确，或者没有在与涡轮航空发动机相关的粒子速度下进行研究。此外，目前工业上使用的数值方法只计算时均流场，而忽略了非定常、湍流运动及其对颗粒行为的影响。因此，一个数值和实验相结合的研究项目应该澄清这个问题。我们将我们的专业知识结合起来，使数值和实验调查相互验证和控制。飞机推进系统研究所将利用其现有的侵蚀试验台，研究现代涡轮喷气发动机高压压气机在典型条件下的回弹行为。研究结果将移交给空气动力学和气体动力学研究所。空气动力学和气体动力学研究所利用其现有的数值流动力学软件，模拟了流动和粒子轨迹。通过双方的深入交流，对平板、带前缘半径板和压气机叶栅的回弹条件进行了数值和实验研究。因此，该项目的目标是开发一种结合实验和数值分析的工具，能够预测工业相关几何形状的回弹和侵蚀行为，目前尚未达到精度。

In the present research proposal, the mechanical damage to material by the impact of solid particles transported in the surrounding fluid, also known as erosion, is to be investigated. The aim is to improve the performance degradation prediction of turbo aero engines by a combined numerical and experimental approach.The erosive particles enter the gas path of the engines as part of the air flow and damage the components, especially the blades. The eroded geometry leads to deviations in the aerodynamics and thus to a deterioration of the performance of the component. The shape change of the components is determined by the trajectory of the particles. Due to the complex geometries of the gas path of aircraft engines, the exact trajectory of these erosive particles is difficult to predict. The trajectories are determined by aerodynamic forces but also by the rebounding behavior of the particles on the walls of the gas path or the blades. Existing rebound models are not accurate enough or have not been investigated at the particle velocities relevant for turbo aero engines. In addition, the numerical methods currently used in industry only compute the time-averaged flow fields and neglect unsteady, turbulent motion and its effect on particle behavior.Therefore, a combined numerical and experimental research project should clarify this question. We combine our expertise in such way that numerical and experimental investigations validate and control each other. With its existing erosion test rig, the Institute of Aircraft Propulsion Systems will investigate the rebound behavior under typical conditions of a high-pressure compressor of a modern turbojet engine. The results are handed over to the Institute for Aerodynamics and Gas Dynamics. The Institute for Aerodynamics and Gas Dynamics, with its existing numerical flow mechanics software, simulates the flow as well as the particle trajectories. Through intensive exchange of the two institutes, the rebound conditions for flat plates, plates with a leading edge radius and a compressor cascade will be studied numerically and experimentally. The aim is therefore to develop a combined experimental-numerical analysis tool during the project that is capable of predicting rebound and erosion behavior in industrially relevant geometries with up-to date not achieved accuracy.