Numerical Investigation of Aero-elasticity in Modern Low-Pressure Turbines

现代航空低压涡轮的一个特点是叶片负荷大，具有复杂的瞬变和分离流型。这种气动非定常流场可能与叶片的结构运动以复杂的非线性方式相互作用，导致颤振和强迫响应失稳。为了检查振动应力水平和确保叶片的机械完整性，了解下一代LPTS颤振发生的物理机制是至关重要的。在本项目中，我们使用一种新的方法来研究现代LPTS的颤振和强迫响应的机理。利用直接数值模拟模型作为计算风洞，研究各种不稳定性源对叶片的力响应和颤振不稳定性的影响。该数值模型还将被用来确定当前低保真数值方法在现代LPT气动机械设计和分析中的相对优点和适当的工作范围。

A feature of modern aeronautical Low Pressure Turbines (LPTs) is their high blade loadings with complex transient and separated flow regimes. This aerodynamic unsteady flow field may interact with blade's structure motion in a complex non-linear fashion leading to flutter and forced response instability. Understanding the physics of onset of flutter for future generations of LPTs is essential in order to examine the vibration stress levels and ensuring blade mechanical integrity. In this project, a novel method is used to explore the mechanism of flutter and forced response in modern LPTs. Using a direct numerical simulation model as a computational wind tunnel, the effects of various sources of unsteadiness on force response and flutter instability of blades will be studied. The numerical model will also be used to identify the relative merits and adequate working range of current low-fidelity numerical methods for modern LPT aeromechanical design and analysis.