High Fidelity, Multiscale Modeling For Eco-Design in Aviation

拟议的研究项目旨在为环保航空开发预测性、多尺度模型和高保真度设计工具。在保持经济效益的同时减少对环境的影响，可能是航空航天和运输行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发展革命性的技术。计算工具对于这些新技术的设计将是非常重要的。******总体和长期目标是促进创新和非常规的设计，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物，如CO2、CO、NOx和烟灰。这些模型是专门为反应和非反应流动的大涡模拟（LES）而开发的。******在短期内，研究计划将侧重于开发精确的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现的数值方案。非结构化网格允许极大的灵活性来表示复杂的工业几何形状。然而，许多精确的子网格模型，如近似反褶积模型，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程序的主要目标之一。******从长远来看，研究的方向将是使用开发的计算工具来进一步了解湍流中有关污染物和噪声的形成和辐射的相干结构的作用。我们的假设是，湍流涡旋拓扑结构的变化显著影响了湍流剪切流的声辐射和湍流反应流中污染物的形成。因此，人们可以通过使用适当设计的喷嘴和混合器来智能地改变湍流涡流的拓扑结构，从而控制和抑制噪声和污染物的形成。******我们将使用数学工具，如代数拓扑和结理论，对直接数值模拟（DNS）和湍流反应和非反应流的LES结果进行后处理，以深入了解湍流涡流拓扑的作用。这些结果有望为湍流、计算气动声学和湍流燃烧的新拓扑理论和模型奠定基础。预计该项目将为灰微射流和叶状混合器等降噪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.