Multi-objective Optimization of Patterned Void Structures

燃气涡轮机发动机的热段部件经历非常高的操作温度和严重的热梯度。因此，发动机部件内产生高应力和应变，从而限制了它们的寿命和可靠性，并增加了发动机维修和大修成本。冷却空气通常用于降低部件温度和热应力。虽然有效，但这种策略减少了可用于燃烧的空气量，导致不完全燃烧，NOx和CO排放量更高。在最近结束的与劳斯莱斯的Engage项目中，我们得出的结论是，空隙可以以最佳形状进行图案化，以减少热段部件中的应力和应变，从而延长发动机寿命。虽然减少应力是至关重要的，但其他方面，如冷却和阻尼，则决定发动机性能。作为Engage的自然延伸，该项目的重点是寻找最佳空隙模式，这些模式可以同时协调燃气涡轮机的以下性能指标：结构完整性、冷却和阻尼，并对制造过程中出现的变化具有鲁棒性。据我们所知，这项工作是新颖的，也是第一次。它需要使用的分析工具，空气流动和应力，制定和解决结构（尺寸，形状和拓扑结构）优化问题，可以有效地处理多个目标，和实验验证的结果，每个有助于解决最佳的蜂窝模式的实施在燃气涡轮机发动机。该项目的成功结果将使罗尔斯·罗伊斯加拿大公司能够设计出更可靠的发动机，同时提高效率和降低排放。此外，该项目将在结构力学、拓扑学和图案化空隙结构和蜂窝材料的多目标优化领域产生宝贵的研究见解（基础和应用），沿着高素质工程师的培训，精通燃气涡轮机技术。

Hot section components of gas turbine engines experience very high operating temperatures and severe thermal gradients. As a result, high stresses and strains develop within engine components, thereby limiting their life and reliability, as well as increasing engine repair and overhaul costs. Cooling air is generally used to reduce component temperature and thermal stresses. While effective, this strategy reduces the amount of air available for combustion, leading to incomplete combustion with higher NOx and CO emissions. In a recently concluded Engage project with Rolls-Royce, we reached to the conclusion that voids can be patterned in optimal shapes to reduce stress and strain in hot-section components, thereby increasing engine life. Whereas stress reduction is crucial, other aspects, such as cooling and damping, govern engine performance. As a natural extension of the Engage, this project focuses on the search of optimal void patterns that can reconcile concurrently the following performance metrics of the gas turbine: structural integrity, cooling, and damping, and be robust to variations emerging from the manufacturing process. To our knowledge, this work is novel and the first of this kind. It requires the use of analysis tools for air flow and stress, the formulation and solution of structural (size, shape and topology) optimization problems that can effectively handle multiple objectives, and the experimental validation of the results, each contributing to address the implementation of optimal cellular patterns in gas turbine engines. A successful outcome from this project will allow Rolls-Royce Canada to design engines with increased reliability while achieving increased efficiency and lower emissions. Furthermore the project will yield invaluable research insights (both fundamental and applied) in the fields of structural mechanics, topology and multi-objective optimization of patterned void structures and cellular materials at large, along with the training of highly qualified engineers, proficient in gas turbine technologies.