Open-source numerical strategy for the analysis and redesign of turbomachine blades accounting for nonlinear structural interactions

在过去的十年里，减少涡轮机械(如飞机发动机和燃气轮机)的环境足迹成为电力和航空航天行业的一个主要问题。虽然已经取得了重大进展，但进一步改进的有希望的途径需要减少与接触或摩擦有关的危险的非线性结构相互作用，特别是对于叶片部件。这对工程师来说是一个主要的障碍，因为叶片设计程序主要是由空气动力学因素驱动的。非线性的结构相互作用充其量是后验的，因此使得现代叶片设计成为一个低效的反复试验的过程。当报告的事故需要重新设计叶片时，这种漫长的设计过程会转化为非常高的成本，因为发电厂必须停止运行，飞机必须停飞。涉及叶轮机械叶片的各种非线性结构相互作用与许多机械界面有关，在这些界面上可能会发生接触或摩擦。对于这些界面中的每一个，最近的研究都导致了预测性特别数值方法的发展。然而，对于每种类型的接口使用不同的数值范例和算法，从而将这些方法区分开来。在此背景下，拟议的研究计划旨在开发一种开放源码的数值策略，用于叶轮机械叶片的分析和重新设计，考虑到非线性结构相互作用。首先，将提出一个统一的数值框架，对叶轮机械叶片的振动响应进行首次全面的多元非线性分析，包括摩擦和结构接触(分别发生在叶片/盘界面和叶片-叶尖/机匣界面)。将以双管齐下的方式审议频率和时间域方法。拟议研究的第二个目标是致力于开发用于非线性结构相互作用的叶尖计时算法。这对于更好地理解与这些相互作用相关的潜在物理现象至关重要。这将通过开发用于产生具有非线性结构相互作用的叶尖定时数据的叶轮机械数字孪生而成为可能。最后，拟议研究方案的最后一个目标与重新设计数值策略有关。它将明显地依赖于满足空气动力学家和结构工程师需求的原创和开放的叶片参数化。从前两个研究目标获得的结果将产生创新的指导方针，这些指导方针将被用于设计针对非线性结构相互作用的稳健叶片。这项研究计划将直接应用于叶轮机械叶片设计的改进，从而在总体能效和维护成本方面取得显着进展。

Over the past decade, reducing the environmental footprint of turbomachines (such as aircraft engines and gas turbines) became a leading issue in both power and aerospace industries. While significant gains have already been made, promising avenues for further improvements require to mitigate hazardous nonlinear structural interactions related to contacts or friction, specifically for bladed components. This is a major roadblock for engineers due to the fact that blade design procedures are mostly driven by aerodynamic considerations. Nonlinear structural interactions are, at best, accounted for a posteriori, thus making modern blade design an inefficient trial-and-error process. When reported incidents call for a blade redesign, this lengthy design process translates into very high costs as power plants must be stopped or planes grounded. The large variety of nonlinear structural interactions involving turbomachine blades is related to the many mechanical interfaces on which contacts or friction may occur. For each of these interfaces, recent research has led to the development of predictive ad-hoc numerical methodologies. However, the use of distinct numerical paradigms and algorithms for each type of interface has compartmentalized these methodologies. In this context, the proposed research program aims at developing an open-source numerical strategy for the analysis and redesign of turbomachine blades, accounting for nonlinear structural interactions. First of all, a unified numerical framework will be proposed to carry out the first comprehensive multi-nonlinear analyses of turbomachine blades' vibration response, including both friction and structural contacts (respectively occurring at the blade/disk interface and at the blade-tip/casing interface). Frequency and time domain methodologies will be considered in a two-pronged verification approach. The second objective of the proposed research focuses on the development of blade-tip timing algorithms dedicated to nonlinear structural interactions. This will be essential to better understand the underlying physical phenomena associated to these interactions. It will be made possible through the development of a turbomachine digital twin for the generation of blade-tip timing data featuring nonlinear structural interactions. Finally, the last objective of the proposed research program relates to the redesign numerical strategy. It will notably rely on an original and open blade parameterization meeting both the needs of aerodynamicists and structural engineers. Results obtained from the two first research objectives will yield innovative guidelines, which will be used to design blades robust with respect to nonlinear structural interactions. This research program will have direct applications for the improvement of turbomachine blade design allowing for significant gains in terms of overall energy efficiency and maintenance cost.