Experimental Study of Soot Nanoparticle Formation and Oxidation at Elevated Pressures

提案编号：CBET-0651906主要研究者：Gomez，Alessandro 所属单位： 耶鲁大学提案标题：在高压下煤烟纳米颗粒形成和氧化的实验研究公开摘要本研究集中在煤烟纳米颗粒在高压下形成的基本原理上，这是一个挑战，因为许多实际系统在这样的条件下操作，但很少有基本数据可用。 由于颗粒物及其表面吸附的多环芳烃对人体健康的影响，燃烧系统排放的烟尘颗粒一直是一个长期存在的环境问题。烟灰的形成也是与可能发生的潜在工程问题相关的技术问题;例如，涡轮机叶片的腐蚀。 尽管近年来取得了相当大的进展，但对实际系统中烟尘形成的基本理解仍然是一个艰巨的挑战。本研究探讨烟灰形成的气体和液体燃料中的逆流燃烧器在高压下运行，高达40个大气压，这是相关的实际应用，如燃气轮机和发动机。待研究的燃料包括乙烯、乙炔、庚烷和甲苯，这是一组具有显著不同的炭黑倾向的气体和液体燃料。研究这些燃料的烟灰形成的主要困难之一是它们非常容易产生烟灰，这个问题在高压下会加剧。如果煤烟产量太多，许多实验的复杂性，使其难以进行基础研究。一个逆流扩散火焰被选为最佳环境的研究，因为无与伦比的控制水平，它提供的烟尘形成过程中，抑制浮力不稳定性，通常困扰同向流火焰在高压下，和建模的机会，在随后的研究系统作为一维。火焰作为一个反应器，其中的烟灰负荷可以？拨了吗从成核阶段开始到显著的表面生长和氧化。作为额外的新奇，通过用高扩散率稀释剂（例如氦气）进行试验，尽管在高压条件下，也可以稳定足够厚的火焰，以使得能够以足够的分辨率探测火焰结构。特别强调的是放在纳米粒子，早期成核阶段。化学物种的特征在于，反映了火焰结构，并参与增长过程。在这项工作的影响中，这项工作的目的是产生一个数据库，用于验证详细的计算模型。将在网上提供数据集，以便研究人员方便地获取数据集，用于随后的建模。研究还将扩展到教学和推广活动。在高压下进行的烟尘研究不容易由没有经验的人进行试验。然而，在研究生和PI的监督下，简单的项目，如SEM/TEM分析和数据简化软件，将由本科生和高中生解决。

Proposal Number: CBET-0651906 Principal Investigator: Gomez, Alessandro Affiliation: Yale UniversityProposal Title: Experimental Study of Soot Nanoparticle Formation and Oxidation at Elevated Pressures PUBLIC ABSTRACTThis research focuses on the fundamentals of soot nanoparticle formation at elevated pressures, a challenge because many practical systems operate at such conditions but few fundamental data are available there. Emission of soot particles from combustion systems has been a long-standing environmental problem because of the health effects associated with particulate matter and the polycyclic aromatic hydrocarbons adsorbed on their surfaces. Soot formation is also an issue of technical relevance for the potential engineering problems that may ensue; e.g., erosion of turbine blades. Despite considerable progress made in recent years, a fundamental understanding of soot formation in practical systems is still a daunting challenge. The present research examines soot formation of gaseous and liquid fuels in a counterflow burner operated at high pressures, up to 40 atm, that are relevant to practical applications such as gas turbines and engines. Fuels to be studied include ethylene, acetylene, heptane and toluene, a set of gaseous and liquid fuels with significantly different sooting propensities. One of the main difficulties of studying soot formation with these fuels is that they are very prone to soot, a problem that is exacerbated at high pressures. If the soot yield is too abundant, a number of experimental complications ensue that make it difficult to perform fundamental studies. A counterflow diffusion flame was selected as an optimal environment for the research because of the unparalleled level of control that it provides on the soot formation process, the suppression of buoyancy instabilities that typically plague co-flow flames at high pressures, and the opportunity of modeling the system in subsequent studies as one-dimensional. The flame is operated as a reactor in which the soot loading can be ?dialed? at will from the onset of the nucleation stage to significant surface growth and oxidation. As an additional novelty, by experimenting with a high diffusivity diluent such as helium, sufficiently thick flames can be stabilized, despite the high-pressure conditions, to enable the probing of the flame structure with adequate resolution. Particular emphasis is placed on the nanoparticle, early-nucleation stage. Chemical species are characterized that reflect the flame structure and participate in the growth process. Among impacts of the work, the effort is intended to yield a database for general use in validation of detailed computational models. Data sets will be made available on the web to allow convenient access to researchers for subsequent modeling. The research will also spill over into teaching and outreach activities. Soot research at high pressure does not lend itself easily to experimentation by inexperienced hands. However, with the supervision of graduate students and the PI, simple projects, such as on SEM/TEM analysis and data reduction software, will be tackled by undergraduate and upper high-school students.