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

在过去的十年中，减少涡轮机（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工业的主要问题。虽然已经取得了显着的进步，有前途的途径，进一步改善需要减轻危险的非线性结构相互作用的接触或摩擦，特别是叶片组件。这是工程师的一个主要障碍，因为叶片设计程序主要由空气动力学因素驱动。非线性结构的相互作用，最好的，占后验，从而使现代叶片设计一个低效的试错过程。当报告的事故需要重新设计叶片时，这一漫长的设计过程将转化为非常高的成本，因为发电厂必须停止运行或飞机必须停飞。叶片的非线性结构相互作用的种类繁多，这与许多可能发生接触或摩擦的机械界面有关。对于每一个这些接口，最近的研究导致了预测特设数值方法的发展。然而，使用不同的数值模式和算法的每种类型的接口划分这些方法。在这种情况下，拟议的研究计划的目的是开发一个开源的数值策略的分析和重新设计的涡轮叶片，占非线性结构的相互作用。首先，将提出一个统一的数值框架，以进行第一次全面的多非线性分析的涡轮叶片的振动响应，包括摩擦和结构接触（分别发生在叶片/盘界面和叶片尖端/机匣界面）。将在双管齐下的核查办法中考虑频域和时域方法。所提出的研究的第二个目标集中在叶尖定时算法的发展，致力于非线性结构相互作用。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。这将有可能通过开发一个数字孪生的非线性结构相互作用的叶尖定时数据的生成。最后，建议的研究计划的最后一个目标涉及到重新设计的数值策略。它将特别依赖于一个原始的和开放的叶片参数化，同时满足空气动力学家和结构工程师的需求。从前两个研究目标获得的结果将产生创新的指导方针，这将被用来设计叶片的非线性结构相互作用的鲁棒性。这项研究计划将直接应用于改进涡轮叶片设计，从而在整体能源效率和维护成本方面获得显着收益。

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.