EAGER: Raman Analysis of Thermophoretically Sampled Soot Particulate

EAGER：热泳采样烟灰颗粒的拉曼分析

• 批准号: 1142284
• 负责人: John Miller
• 金额: $ 9.91万
• 依托单位: George Washington University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1142284&HistoricalAwards=false
• 关键词: EAGER; Raman; Analysis; Thermophoretically; Sampled

1142284MillerIntellectual Merit: Soot is the term given to small particles that are mostly composed of carbon, and that result from incomplete combustion processes. Soot formation plays both positive roles (radiation from hot particles is the dominant mechanism for heat transfer in boilers) and negative (in the same boilers, soot may coat furnace walls and soot particle impingement on the turbine blades of a commercial airline engine leads to wear) in energy generation. Soot is also important in the environment as it increases mortality in urban areas and contributes to climate change.In the laboratory, what we understand about soot formation comes from measurements near the beginning (through the measurements of concentrations of small precursor molecules) and near the end (through optical measurements in flames and/or microscopic analysis of collected particulate matter) of the process. As a consequence, there are several fundamental questions that have gone unanswered: What is the mechanism for the transition from flat, planar molecules to three-dimensional particles? What is the nature of the carbon bonding in the youngest particles? The goal of this project is to answer these questions through a study of particles sampled from several types of flames. By understanding the detailed chemistry and physics of soot formation and destruction in flames, we enable combustion system engineering that can enhance the positive effects of soot in flames (heat transfer) and while minimizing deleterious heath effects and environmental impacts. The project's principal investigator has been a leader in the science of soot formation for more than 20 years. In the 1980s, he proposed that soot particles are composed of aggregates of flat, and extremely stable, molecules known as polynuclear aromatic hydrocarbons (PAH). His calculations suggest that the binding energy that holds clusters of PAH together is strong enough for them to survive even at flame temperatures. To prove this hypotheses, in this project particles are studied using Raman spectroscopy, in which laser light is "scattered" from the carbon particles, providing information about the optical and electronic properties of the particles, which can then be used to infer structure and morphology. Analysis is performed on particles that are rapidly extracted from laboratory flames that mimic a wide range of conditions found in practical combustion devices.Broader Impacts: In addition to the technical motivation for the project described above, an additional outcome of this award will be the education of a doctoral student in the Chemistry Department of GWU. The GWU Ph.D. program is smaller than most US doctoral chemistry programs. However, its size has been an attribute in attracting top-quality students who are looking for the type of individual attention that is available there. Its small size has catalyzed interdisciplinary research that links the chemistry program with scientists and engineers with mutual interests at GW, at other US academic campuses and laboratories, and at partner institutions throughout the world. This strategy has been a successful recipe in insuring that their graduates find employment in both the public and private sectors. George Washington University is ranked among the top few universities in the country in the population of women in science and engineering graduate programs. In line with this fact, the chemistry department's graduate program and the PI's lab have majority female populations.

[142284]米勒知识价值：煤烟是指主要由碳组成的小颗粒，是不完全燃烧过程的结果。烟灰的形成在发电中既有积极作用（热颗粒的辐射是锅炉传热的主要机制），也有消极作用（在同一锅炉中，烟灰可能会覆盖炉壁，烟灰颗粒撞击商用航空发动机涡轮叶片导致磨损）。煤烟对环境也很重要，因为它增加了城市地区的死亡率，并导致了气候变化。在实验室中，我们对烟灰形成的了解来自于该过程开始时（通过测量小前体分子的浓度）和接近结束时（通过火焰中的光学测量和/或收集的颗粒物的微观分析）的测量。因此，有几个基本问题没有得到解答：从平坦的平面分子到三维粒子的转变机制是什么？最年轻粒子中的碳键的性质是什么？这个项目的目标是通过研究从几种类型的火焰中取样的粒子来回答这些问题。通过了解火焰中煤烟形成和破坏的详细化学和物理，我们使燃烧系统工程能够增强火焰中煤烟的积极作用（传热），同时最大限度地减少有害的健康影响和环境影响。20多年来，该项目的首席研究员一直是煤烟形成科学的领导者。在20世纪80年代，他提出烟尘颗粒是由扁平的、极其稳定的多核芳香烃（PAH）分子聚集而成。他的计算表明，将多环芳烃聚集在一起的结合能足够强，即使在火焰温度下也能存活。为了证明这一假设，在这个项目中，粒子使用拉曼光谱进行研究，其中激光从碳粒子中“散射”，提供关于粒子的光学和电子特性的信息，然后可以用来推断结构和形态。对从模拟实际燃烧装置中发现的各种条件的实验室火焰中快速提取的颗粒进行分析。更广泛的影响：除了上述项目的技术动机外，该奖项的另一个成果将是在GWU化学系培养一名博士生。华盛顿大学的博士项目比大多数美国化学博士项目要小。然而，它的规模一直是吸引高质量学生的一个因素，这些学生正在寻找那里可以提供的个人关注。它的小规模催化了跨学科研究，将化学项目与华盛顿大学、其他美国学术校园和实验室以及世界各地合作机构的科学家和工程师联系在一起。这一策略在确保他们的毕业生在公共和私营部门找到工作方面是一个成功的秘诀。在科学和工程研究生项目的女性人数方面，乔治华盛顿大学是美国排名前几位的大学之一。与这一事实相一致的是，化学系的研究生项目和PI的实验室以女性为主。