Experimental study of local extinction in laminar and turbulent flames

层流和湍流火焰中局部消光的实验研究

• 批准号: 1552074
• 负责人: Michael Renfro
• 金额: $ 19.37万
• 依托单位: University of Kentucky Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1552074&HistoricalAwards=false
• 关键词: Experimental; study; local; extinction; laminar

1336184RenfroIn many practical combustors, heat is released by chemical reactions in relatively thin flame sheets. Turbulence in the flow of fuel and air in the combustor lead to fluctuations in velocity that perturb the flame sheet and increase the transfer of heat away from the flame. When these fluctuations are sufficiently large, the heat loss can be too high compared to the heat released by the flame resulting in local extinction. A local extinction event leaves a hole in the flame sheet that can lead to complete extinction of the flame. In many applications extinction is a significant limitation to the operation of the combustor, while in other applications extinction can be desired to quench a flame. In either case, physical understandings of the mechanisms that cause extinction are needed. This project seeks a fundamental understanding of the interactions of velocity and flame sheets that cause local extinction such that more accurate models of flame limits and the response of flame holes can be generated. The intellectual merit of the work focuses on a detailed understanding of the impact that velocity fluctuations in turbulent flames have on heat transfer from flames sheets as well as the impact of these changes to the flame's chemical heat release. The experimental and computational project will utilize an optically-accessible combustor that has been designed to create local extinction in a flame sheet enabling a detailed study using laser diagnostics. The measurements will be used to develop models describing extinction that can have broader impact on industrial design tools. The research will involve the participation of graduate and undergraduate students, who will be trained in fundamental combustion theory and application of optical measurements.

1336184肾上腺素许多实用的燃烧器，由化学反应在相对较薄的火焰片中释放。 燃烧器中燃料和空气流的湍流导致速度波动，使火焰板扰动，并增加热量从火焰中移开。 当这些波动足够大时，与火焰释放的热量相比，热量损失可能太高。 一个局部灭绝事件在火焰板上留下一个孔，可导致火焰完全灭绝。 在许多应用中，灭绝是对燃烧器运行的重要限制，而在其他应用中，可以灭绝以淬火火焰。 无论哪种情况，都需要对引起灭绝的机制进行物理理解。 该项目寻求对导致局部灭绝的速度和火焰表相互作用的基本了解，从而可以产生更准确的火焰限制模型和火焰孔的响应。 这项工作的智力优点集中在详细了解速度在湍流火焰中对火焰片传热的影响以及这些变化对火焰化学热释放的影响的影响。 实验和计算项目将利用一种旨在在火焰片中创建局部灭绝的光学上可访问的燃烧器，从而实现了使用激光诊断的详细研究。 这些测量将用于开发描述灭绝的模型，这些模型可能会对工业设计工具产生更大影响。 这项研究将涉及研究生和本科生的参与，他们将接受有关基本燃烧理论和光学测量应用的培训。