High Fidelity, Multiscale Modeling For Eco-Design in Aviation

拟议的研究计划旨在为生态友好型航空开发预测性，多尺度模型和高保真设计工具。 减少对环境的影响，同时保持经济盈利能力，也许是航空航天和运输业以及能源部门面临的最重大的技术挑战。 对排放水平日益严格的限制要求开发革命性的技术。计算工具对于设计这种新技术将具有重要意义。 总体和长期目标是为创新和非常规设计做出贡献，以减少飞机噪音和发动机污染物。在短期内，该计划的重点是在非结构化网格求解器上引入多尺度、现象学模型和高保真度计算工具，以预测飞机噪声和燃烧副产品，如CO2、CO、NOx和烟尘。这些模型是特别开发的反应和非反应流的大涡模拟（LES）。 在短期内，该研究计划将专注于开发准确和数学上一致的模型，以及特别适合在非结构化网格求解器中实施的数值方案。非结构化网格允许显著的灵活性来表示复杂的工业类型几何形状。然而，许多精确的亚网格模型，如近似反卷积模型，只适用于结构网格。扩展和验证这种模型的非结构化网格是这个计划的主要目标之一。 从长远来看，研究的方向将是使用先进的计算工具，以进一步了解湍流中相干结构对污染物和噪声的形成和辐射的作用。我们的假设是，湍流涡旋的拓扑结构的变化显着影响声辐射的湍流剪切流和污染物的形成在湍流反应流。因此，人们可以通过使用适当设计的喷嘴和混合器智能地改变湍流涡流的拓扑结构来控制和抑制噪声和污染物的形成。 我们将采用数学工具，如代数拓扑和纽结理论的直接数值模拟（DNS）和LES的湍流反应和非反应流的后处理结果，以获得有关湍流涡旋拓扑结构的作用的见解。研究结果为湍流、计算气动声学和湍流燃烧等领域的新拓扑理论和模型奠定了基础。预计该计划还将为灰微射流和波瓣混合器等噪声抑制装置的有效设计方法以及低排放燃烧室的新概念铺平道路。

The proposed research program broadly aims to develop predictive, multiscale models and high fidelity design tools for eco-friendly aviation. Reducing the environmental impact, while maintaining economic profitability, is perhaps the most significant technical challenge faced by aerospace and transportation industries, as well as the energy sector. The increasingly stringent restrictions on emission levels require the development of revolutionary technologies. Computational tools will be of significant importance for the design of such new technologies. The overarching and long-term goal is to contribute toward innovative and unconventional designs to reduce aircraft noise and engine pollutants. In the short term, the proposed program focuses on introducing multiscale, phenomenological models, and high fidelity computational tools on unstructured-grid solvers to predict aircraft noise and combustion byproducts such as CO2, CO, NOx, and soot. These models are in particular developed for Large Eddy Simulation (LES) of reacting and nonreacting flows. In the short term, the research program will be focused on developing accurate and mathematically consistent models, and numerical schemes that are specifically suitable for implementation in unstructured-grid solvers. Unstructured grids allow for significant flexibility to represent complex, industrial-type geometries. However, many accurate subgrid models such as Approximate Deconvolution Models have only be applied to structured-grids. The extension and verification of such models for unstructured grids is one of the main goals of this program. In the long term the research will be directed toward using the developed computational tools to obtain further insight into the role of coherent structures in turbulent flows with respect to the formation and radiation of pollutants and noise. Our hypothesis is that changes in the topology of turbulent eddies significantly affect sound radiation by turbulent shear flows and pollutants formation in turbulent reacting flows. Therefore, one can control and suppress noise and pollutants formation by intelligently changing the topology of turbulent eddies through the use of properly designed nozzles, and mixers. We will employ mathematical tools such as Algebraic Topology and Knot Theory to postprocess results from Direct Numerical Simulations (DNS) and LES of turbulent reacting and nonreacting flows to obtain insight about the role of turbulent eddies topology. The results are expected lay the foundation for new topological theories and models in turbulence, computational aeroacoustics, and turbulent combustion. It is also expected that this program would pave the path for effective design methodologies of noise suppression devices such ash microjets and lobed mixers, and new concepts for low-emission combustion chambers.