This thesis describes the effects of operational parameters upon aeroengine flutter stability. The study is composed of three parts: theoretical development of relevant parameters, exploration of a computational model, and analysis of fully scaled test data. Results from these studies are used to develop a rational flutter clearance methodology-a test procedure to ensure flutter-free operation. It is shown, under conditions relevant to aeroengines, that four nondimensional parameters are necessary and sufficient for flutter stability assessment of a given rotor geometry. We introduce a new parameter, termed the reduced damping, g/p*, which collapses the combined effects of mechanical damping and mass ratio (blade mass to fluid inertia). Furthermore, the introduction of the compressible reduced frequency, K*, makes it possible to uniquely separate the corrected performance map from the non-dimensional operating environment (including inlet temperature and pressure).
展开▼
机译:本文描述了运行参数对航空发动机颤振稳定性的影响。这项研究由三部分组成:相关参数的理论开发,计算模型的探索以及全面测试数据的分析。这些研究的结果用于开发合理的颤振清除方法-一种测试程序,以确保无颤动运行。结果表明,在与航空发动机有关的条件下,对于给定转子几何形状的颤振稳定性评估,必须使用四个无量纲参数,这些参数是足够的。我们引入了一个新参数,称为减小的阻尼g / p *,它使机械阻尼和质量比(叶片质量与流体惯性)的综合作用崩溃了。此外,引入可压缩的降低频率K *使得可以将校正后的性能图与无量纲的操作环境(包括入口温度和压力)唯一地分开。
展开▼