Flame-Vortex Interaction Studies to Reduce Pollutants from Engines

减少发动机污染物的火焰涡相互作用研究

• 批准号: 9123834
• 负责人: James Driscoll
• 金额: $ 23.92万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-01 至 1995-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9123834&HistoricalAwards=false
• 关键词: Flame; Vortex; Interaction; Studies; Reduce

The goal of this work is to understand how flame stretch and flame curvature affect premixed flame properties. A laminar vortex will be created in an existing test apparatus and will be interacted with a laminar premixed flame. Vortex conditions first will be chosen to represent a single eddy in a turbulent flow to show how strain and flame curvature affect the local burning velocity, the creation of pockets of unburned CO pollutants, flame extinction, and deviations from the "laminar flamelet" profiles of temperature and OH concentration. Secondly, vortex conditions later will be chosen to represent the piston-generated vortex of an internal combustion engine and the vortex will be interacted with a centrally ignited flame kernel in order to understand kernel growth in a realistic strain field. Thirdly, the measurements will be used to assess and improve a recent full Navier-Stokes CFD simulation of the laminar flame-vortex interaction, which forms the "building block" of future models and can provide a useful submodel for existing statistical models. Operational diagnostics to be employed include Rayleigh scattering for temperature images and profiles, OH and NO fluorescence imaging, and PIV to image the two-dimensional strain field. This study should provide information useful to a number of other research efforts in the area of turbulent premixed flame structures. In particular, it should be of use in development of better simulations of flame-vortex interactions, leading to better understanding and modeling of critical processes affecting levels of production of carbon monoxide and oxides of nitrogen in devices such as internal combustion engines, in which flame-vortex interactions play a crucial role. This in turn will lead to definition of design strategies for reduction of levels of these pollutants produced by such engines, an important national need.

这项工作的目的是了解火焰拉伸和火焰曲率如何影响预混火焰的性质。层流涡流将在现有的试验装置中产生，并将与层流预混火焰相互作用。首先将选择涡旋条件来表示湍流中的单个涡流，以显示应变和火焰曲率如何影响局部燃烧速度、未燃烧CO污染物的形成、火焰熄灭以及偏离温度和OH浓度的“层流火焰面”轮廓。其次，后面将选择涡流条件来表示内燃机活塞产生的涡流，并将该涡流与中心点燃的火核相互作用，以了解真实应变场中的火核生长。第三，测量结果将被用来评估和改进最近对层流火焰-涡旋相互作用的完整的Navier-Stokes CFD模拟，该模拟构成了未来模型的“积木”，并可以为现有的统计模型提供有用的子模型。使用的操作诊断方法包括用于温度图像和轮廓的瑞利散射、OH和无荧光成像，以及用于对二维应变场进行成像的PIV。这项研究将为湍流预混火焰结构领域的其他一些研究工作提供有用的信息。特别是，它应该用于开发更好的火焰-涡旋相互作用模拟，从而更好地理解和模拟影响内燃机等设备中一氧化碳和氮氧化物产生水平的关键过程，其中火焰-涡旋相互作用发挥关键作用。这反过来将导致设计战略的定义，以减少这些发动机产生的这些污染物的水平，这是一个重要的国家需求。