CAREER: Fundamental Analysis and Computational Modeling of Acoustic Radiation in Turbulent Reacting Flows

0844587该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。本研究旨在通过研究湍流反应流和开发计算模型，为喷气式飞机噪声污染的控制提供新的、有用的见解。高涵道比涡扇发动机显著降低了喷气噪声，使燃烧噪声成为主要的噪声来源。此外，新的清洁燃烧技术产生了增加燃烧噪音的不良影响。由于对这些现象的科学理解有限，预测建模能力在很大程度上是不可用的，这迫使在地面上实施昂贵的被动降噪计划。将通过基础分析、发展美国国家科学基金会TeraGrid系统的预测建模能力和实验验证来寻求对这种声辐射的基本理解。将对湍流预混、部分预混和扩散火焰进行基准火焰构型的直接数值模拟，以识别和了解控制声辐射的过程。利用这些知识，将开发一种一致的建模能力，适用于燃烧LES的可靠噪声预测。该模型将在具有实验数据的复杂火焰结构的模拟中得到验证。这些详细的模拟数据将对识别声源、理解声-热化学耦合机制、表征声折射效应和指导实验仪器具有重要价值。在这项研究中开发的模型能力也可以集成到模拟工具中，用于设计飞机发动机，燃气轮机和其他应用中的先进燃烧系统。这种对噪声机制的改进理解也可能与发电领域以外的领域有潜在的相关性，例如声学传感和处理太阳声振荡的日震应用。全面的教育和外展计划是CAREER奖助金的一部分。它特别强调从直接受到飞机噪音污染影响的当地机场附近社区招募代表性不足的高中生。通过暑期实习和与本科生密切互动，通过课堂项目解决他们可能涉及的各种噪音和空气污染方面的具体问题，这些高中生将被鼓励从事工程职业，从事对他们的社区有直接利益的问题。教育计划的另一个组成部分是通过研究活动、暑期学校和本科课程，让一群有动力的、多样化的本科生接触到计算建模和高性能计算。随着越来越多地使用计算建模来解决我们世界的技术挑战，在他们的职业生涯早期获得这些技能变得越来越重要。

0844587IhmeThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This research is intended to achieve new, useful insights into control of noise pollution from jet aircraft by studying turbulent reactive flows and developing computational models. Remarkable reductions in jet noise have been achieved with high-bypass turbofan engines, which made combustion noise a leading noise contributor. Furthermore, new clean-combustion technologies have had the unwanted effect of increasing combustion noise. Predictive modeling capabilities are not available largely because of the limited scientific understanding of these phenomena, which forces the implementation of costly passive sound-mitigating programs on the ground.Fundamental understanding of this acoustic radiation will be sought by combining fundamental analysis, development of predictive modeling capabilities on the NSF TeraGrid system, and experimental validation. Direct numerical simulations of benchmark flame configurations will be conducted on turbulent premixed, partially premixed, and diffusion flames to identify and understand the processes controlling acoustic radiation. Using this knowledge, a consistent modeling capability will be developed applicable for reliable noise predictions in combustion LES. This model will be validated in simulations of complex flame configurations for which experimental data are available. Such detailed simulation data will be valuable in identifying acoustic sources, understanding acoustic-thermochemical coupling mechanisms, characterizing sound-refraction effects, and guiding experimental instrumentation. Model capabilities developed in this research can also be integrated into simulation tools for designing advanced combustion systems in aircraft engines, gas turbines, and other applications. This improved understanding of noise mechanism could also be of potential relevance to areas outside the power generation field, such as acoustic sensing and helioseismic applications that deal with solar-acoustic oscillations.A comprehensive education and outreach program is part of this CAREER grant. Its particular emphasis is to recruit underrepresented high-school students from communities in proximity to local airports that are directly affected by aircraft noise pollution. Through summer internships and the close interaction with undergraduate students through classroom projects on specific problems addressing various noise and air pollution aspects they can relate to, these high school students will be encouraged to pursue engineering careers to work on issues that have a direct benefit to their community. Another component of the education plan is to expose a group of motivated and diverse undergraduate students to computational modeling and high-performance computing through research activities, summer schools, and undergraduate curricula. Acquiring such skills early in their careers is increasingly important with the growing use of computational modeling to solve the technological challenges of our world.