Simulation and modeling of soot formation and transport in turbulent flames

1403403 Lignell火焰排放的烟尘是一种污染物，对健康有害，并影响传热。碳烟的形成是一个具有挑战性的问题，涉及到非平凡的火焰相互作用在很宽的范围内的条件下，在他们的大小和时间。 人们的努力集中在煤烟是如何在实际的火焰中形成的，这些火焰通常嵌入在湍流中，例如喷气发动机和熔炉中的火焰。 将开发计算机模型并进行验证。 研究进展将通过出版物，演示文稿和网络进行交流。 研究生和本科生将在计算燃烧方面接受指导和培训。 小学生将通过火焰和流动演示介绍工程师的工作，让学生仔细观察燃烧是如何推动社会的。高中毕业生将由本科生指导，因为他们参加了一个初级流体力学课程项目，其中小组定义一个问题，收集和分析数据，并提出结果。这项工作将通过应用三种模拟方法来解决湍流烟尘建模中的问题：一维湍流（ODT）、直接数值模拟（DNS）和大涡模拟（LES），在一项研究中了解烟尘的形成和传输，并验证工程模拟中使用的模型。 考虑了四项任务：（1）将一致的烟尘模型应用到模拟代码中;（2）进行ODT、DNS和LES模拟，以了解烟尘-火焰相互作用;（3）评估次网格烟尘模型;（4）对小学和高中学生进行教育推广。 然而，解决所有尺度的唯一模拟方法是DNS，这对于实际流来说是非常昂贵的。 对于DNS和LES，模型需要低于某些尺度，因为精细尺度信息不可用。 这项工作将使用ODT，DNS和LES来了解基本的烟尘-火焰-燃烧-辐射相互作用，并量化烟尘传输模型。 ODT和LES将进行比较，以及表征实验射流火焰。 这些模式的长处结合起来使用，可以弥补其弱点，并为需要研究的领域提供指导。

1403403LignellSoot emission from flames is a pollutant, a health hazard, and affects heat transfer. Soot formation is a challenging problem that involves non-trivial flame interactions over a wide range of conditions in their size and time. Efforts are focused on how soot forms in practical flames that are usually embedded in turbulence, such as those in jet engines and furnaces. Computer-based models will be developed and their validation will be carried out. Research advances will be communicated through publication, presentation, and on the web. Graduate and undergraduate students will be mentored and trained in computational combustion. Elementary school students will be introduced to what engineers do through flame and flow demonstrations that get students to look carefully at how combustion drives society. High school seniors will be mentored by undergraduate students as they participate in a junior-level fluid mechanics course project where groups define a problem, gather and analyze data, and present results.This work will address problems in turbulent soot modeling by applying three simulation approaches: one-dimensional turbulence (ODT), direct numerical simulation (DNS), and large eddy simulation (LES), in a single study to understand soot formation and transport, and to validate models used in engineering simulations. Four tasks are considered: (1) implementing consistent soot models into simulation codes; (2) performing ODT, DNS, and LES simulations to understand soot-flame interactions; (3) evaluating subgrid soot models; and (4) educational outreach to elementary and high school students. However, the only simulation approach that resolves all scales is DNS, which is prohibitively expensive for practical flows. For DNS and LES, models are needed below certain scales, because fine-scale information is not available. This work will use ODT, DNS, and LES to understand fundamental soot-flame-turbulence-radiation interactions, and quantify soot transport models. ODT and LES will be compared to well-characterized experimental jet flames. The strengths of these models, used together, complement their weaknesses and provide guidance as to where research needed.