CAREER: Impact of Turbulence on Mechanisms of Combustion Instability

职业：湍流对燃烧不稳定机制的影响

• 批准号: 1749679
• 负责人: Jacqueline O'Connor
• 金额: $ 50万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-06-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1749679&HistoricalAwards=false
• 关键词: CAREER; Impact; Turbulence; Mechanisms; Combustion

Combustion instability is an issue that affects many critical power and propulsion technologies, including jet engines, power-generation gas turbines, rockets, boilers, and process furnaces. Significant questions remain about how turbulence alters flame behavior during instability. In particular, in high-performance engines, does the turbulence/flame interaction change the instability feedback mechanisms and do the present numerical models include the correct physics? The proposed work addresses these questions using a systematic experimental approach to examine various key aspects of combustion instability. Advanced laser diagnostics will be used to image the flowfield and the flame, unlocking the coupling between turbulence and the instability feedback loop. The PI will also work with many other early-career faculty to effectively disseminate the results of this research and enhance the educational experience of students. In particular, the PI will facilitate an online network of early-career researchers to share research and teaching materials. This will ease the transition into faculty careers and promote high-quality thermofluids education at universities across the United States.The technical goal of the proposed work is to understand the impact of turbulence on three critical components of the thermoacoustic feedback loop: the hydrodynamic instability of the flowfield that determines the susceptibility of the flow to external disturbances; the coupling mechanisms that drive heat release rate oscillations; and the mechanism by which these disturbances create heat release rate oscillations in non-flamelet regimes. This systematic approach uses theory-based experimental design to probe the ways in which turbulence impacts flow stability, coupling-mechanism physics, and flame behavior within the framework of combustion instability. The overarching intellectual merit contribution will be made in the formulation of the combustion instability regime diagram that describes the behavior of flames during thermoacoustic instability over a range of operating conditions. In following this framework, this work will have significant impacts on fundamental understanding of turbulent flames and combustion instability, the ability to predict combustion instability in industry-relevant devices, and the PIs career development. The results of this work will also feed into the development, implementation, and dissemination of case studies for undergraduate and graduate audiences. The case studies will focus on combustion-related issues, exposing a range of students to the importance of combustion in society; case studies will be disseminated through a network of early-career faculty through an online portal. The development of the case studies is rooted in theory-based educational design, including best-practices for the formation of online content, research-based techniques for improving recruitment and retention of under-served student populations, and the robust development of a community of practice for early-career faculty centered on incorporating combustion science into the classroom.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

燃烧不稳定性是一个影响许多关键动力和推进技术的问题，包括喷气发动机、发电燃气轮机、火箭、锅炉和工艺炉。在不稳定性期间，湍流如何改变火焰行为仍然存在重要问题。特别是在高性能发动机中，湍流/火焰相互作用是否改变了不稳定性反馈机制，以及目前的数值模型是否包括正确的物理机制？建议的工作解决这些问题，使用系统的实验方法来研究燃烧不稳定性的各个关键方面。先进的激光诊断将用于流场和火焰的成像，解开湍流和不稳定反馈回路之间的耦合。PI还将与许多其他早期职业教师合作，有效地传播这项研究的成果，并提高学生的教育经验。特别是，PI将促进早期职业研究人员的在线网络共享研究和教学材料。这项工作的技术目标是了解湍流对热声反馈回路三个关键组成部分的影响：流场的流体动力学不稳定性，它决定了流场对外部扰动的敏感性;驱动热释放率振荡的耦合机制;以及这些扰动在非小火焰状态下产生热释放率振荡的机制。这种系统的方法使用基于理论的实验设计，以探讨湍流影响流动稳定性，耦合机制的物理，燃烧不稳定性的框架内的火焰行为的方式。总体的智力价值的贡献将在制定的燃烧不稳定状态图，描述了在一系列的操作条件下的热声不稳定的火焰的行为。在这个框架下，这项工作将对湍流火焰和燃烧不稳定性的基本理解，预测工业相关设备中燃烧不稳定性的能力以及PI的职业发展产生重大影响。这项工作的结果也将投入到为本科生和研究生受众制定、实施和传播案例研究中。案例研究将侧重于燃烧相关的问题，让一系列学生了解燃烧在社会中的重要性;案例研究将通过在线门户网站通过早期职业教师网络传播。案例研究的发展植根于以理论为基础的教育设计，包括形成在线内容的最佳做法，改善服务不足学生群体的招聘和保留的研究技术，一是大力发展早期实践社区，该奖项反映了NSF的法定使命，并被认为是值得的通过使用基金会的知识价值和更广泛的影响审查标准进行评估来提供支持。

项目成果

Role of Turbulence in Precessing Vortex Core Dynamics

湍流在进动涡核动力学中的作用

• 发表时间: 2019
• 期刊: ASME Turbo Expo
• 作者: Karmarkar, Ashwini;Frederick, Mark;Clees, Sean;Mason, Danielle;O'Connor, Jacqueline
• 通讯作者: O'Connor, Jacqueline

Impact of turbulence on the coherent flame dynamics in a bluff-body stabilized flame

• DOI: 10.1016/j.proci.2020.08.059
• 发表时间: 2021-04-10
• 期刊: PROCEEDINGS OF THE COMBUSTION INSTITUTE
• 影响因子: 3.4
• 作者: Karmarkar, Ashwini;Tyagi, Ankit;O'Connor, Jacqueline
• 通讯作者: O'Connor, Jacqueline

Impact of precessing vortex core dynamics on the thermoacoustic instabilities in a swirl-stabilized combustor

旋流稳定燃烧室中进动涡核动力学对热声不稳定性的影响

• DOI: 10.1017/jfm.2022.610
• 发表时间: 2022
• 期刊: Journal of Fluid Mechanics
• 影响因子: 3.7
• 作者: Karmarkar, Ashwini;Gupta, Saarthak;Boxx, Isaac;Hemchandra, Santosh;O'Connor, Jacqueline
• 通讯作者: O'Connor, Jacqueline

Relative Effects of Velocity- and Mixture-Coupling in a Thermoacoustically Unstable, Partially Premixed Flame

热声不稳定、部分预混火焰中速度耦合和混合耦合的相对效应

• DOI: 10.1115/1.4052262
• 发表时间: 2022
• 期刊: Journal of Engineering for Gas Turbines and Power
• 作者: Karmarkar, Ashwini;Boxx, Isaac;O'Connor, Jacqueline
• 通讯作者: O'Connor, Jacqueline

Understanding the role of flow dynamics in thermoacoustic combustion instability

• DOI: 10.1016/j.proci.2022.07.115
• 发表时间: 2022-10
• 期刊: Proceedings of the Combustion Institute
• 影响因子: 3.4
• 作者: J. O’Connor