Study on Physics and Chemistry of Distributed Combustion for Reducing Pollutants

分布式燃烧减排的物理与化学研究

• 批准号: 1703543
• 负责人: James Driscoll
• 金额: $ 28万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-15 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1703543&HistoricalAwards=false
• 关键词: Study; Physics; Chemistry; Distributed; Combustion

This research will provide understanding of new ways to burn low-carbon fuels (such as natural gas) and zero-carbon fuels (such as hydrogen) in a new combustion mode called distributed (or flameless) combustion. Previous experiments have shown that flameless combustion produces ultra-low levels of pollutants (nitric oxide and carbon monoxide) and is ideal for proposed low-carbon fuels. However, previous work was trial-and-error; the reasons for the improvement, the practical limitations and the underlying physics were not measured. This research will employ the unique laser sheet kilohertz imaging diagnostics of the PI to take high speed movies of the chemical reaction layers and local gas temperatures within this new mode of flameless combustion for the first time. The resulting experimental data base should provide the understanding needed to optimize the operating conditions and minimize pollutants. The data base will be disseminated to allow others to develop design models based on advanced computer codes. A specially-designed flameless combustor experiment will be operated at large values of preheat gas temperature, internal gas recirculation, turbulence levels, gas pressure and air staging. For the first time, the chemistry that occurs within this mode of combustion will be measured. Fuels will be selected that promote auto ignition (dimethyl ether, propane and hydrogen-CO synfuel) in addition to natural gas. The HO2 radical plays an important role in the chemistry, as well as formaldehyde and hydroxyl. Concentrations of these species will be measured simultaneously for the first time using the new fluorescence methods of the PI. Of particular interest is seeing how turbulent eddies enter into the chemical reaction layers and broaden them, which reduces the temperature gradients and provides a more uniform combustion with less nitric oxide formation. Gas velocity field imaging at kilohertz framing rates will be conducted provide high speed movies and information about the fundamental physical processes. The boundaries between this new regime of flameless combustion and conventional flames will be recorded. The relationship between the time scales of flameless and auto-ignition chemistry will be measured. This research is being conducted within a highly turbulent and realistic engine environment and should provide a bridge between these realistic, turbulent conditions and several NSF-funded chemistry studies of auto ignition that are being conducted in bench top chemistry labs.

这项研究将提供对燃烧低碳燃料(如天然气)和零碳燃料(如氢气)的新方法的理解，这种新的燃烧模式称为分布式(或无焰)燃烧。此前的实验表明，无焰燃烧产生超低水平的污染物(一氧化氮和一氧化碳)，是拟议中的低碳燃料的理想选择。然而，以前的工作是试错的；改进的原因、实际限制和潜在的物理学没有被测量。这项研究将首次使用PI独特的激光片式千赫成像诊断来拍摄这种新的无焰燃烧模式下的化学反应层和局部气体温度的高速电影。由此产生的实验数据库应提供优化操作条件和将污染物降至最低所需的理解。该数据库将被传播，以使其他人能够根据先进的计算机代码开发设计模型。一个特别设计的无焰燃烧室实验将在预热气体温度、内部气体再循环、湍流级别、气体压力和空气分级的较大值下进行。将第一次测量在这种燃烧模式下发生的化学物质。除天然气外，还将选择促进汽车点火的燃料(二甲醚、丙烷和氢-一氧化碳合成燃料)。HO2自由基以及甲醛和羟基在化学中起着重要的作用。这些物种的浓度将首次使用PI的新荧光方法同时测量。特别令人感兴趣的是观察湍流涡流如何进入化学反应层并使其加宽，这降低了温度梯度，提供了更均匀的燃烧，生成的一氧化氮更少。将在千赫成帧速率下进行气体速度场成像，提供关于基本物理过程的高速电影和信息。这一新的无焰燃烧制度和传统火焰之间的界限将被记录下来。将测量无焰化学和自燃化学的时间尺度之间的关系。这项研究是在高度湍流和现实的发动机环境中进行的，应该在这些现实的湍流条件和NSF资助的几项正在台式化学实验室进行的汽车点火化学研究之间架起一座桥梁。