Shock Tube/Laser Absorption Measurements of Hydroperoxyl Radical Reactions

氢过氧自由基反应的激波管/激光吸收测量

• 批准号: 0964884
• 负责人: Ronald Hanson
• 金额: $ 35万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2015-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0964884&HistoricalAwards=false
• 关键词: Shock; Tube; Laser; Absorption; Measurements

0964884Hanson There is a critical need for the measurement of elementary reaction rates for species and reactions relevant to combustion. Our ability to model combustion processes with high fidelity relies on the existence of accurate measurements of fundamental reaction rates of a smaller set of key reactions that control the reaction progress. This project proposes to measure the high-temperature rate coefficients for reactions of HO2 with CH3, C2H5, HO2, and OH. These reactions have been difficult to measure because of both the highly reactive nature of the reactants and the challenges in developing quantitative and sensitive diagnostics for the reactant and product concentrations. These reactions have been identified as major contributors to the uncertainty in the modeling of hydroperoxyl radical concentration in combustion systems. Measurements of these reaction rates will be performed in high-purity shock tubes using UV laser absorption of OH, HO2, H2O2, and CH3 radicals and mid-IR laser absorption of H2O. The overall range of temperature and pressure to be studied is from 800 to 2200 K and from 0.5 atm to 10 atm. This work will take advantage of a recently acquired tunable ultra-fast (76 MHz) quasi-CW laser system for ready access to broad deep-UV absorption transitions and recent advances in distributed feedback diode lasers in the mid-IR.Intellectual MeritReactions involving the hydroperoxyl radical (HO2) play an important role in oxidation pathways of hydrogen and hydrocarbons. Much of what we already know about the role of these hydroperoxyl radical reactions has been derived from lower temperature (below 800 K) experiments, or from estimates. Direct experimental results for these reactions at high temperatures are rare (or non-existent) or contradictory, and are critically needed to enable development and validation of combustion kinetic models. The development of new and sensitive species diagnostics methods are also needed to advance these studies.Broader ImpactThis research will provide an opportunity to train a new generation of engineering scientists in modern combustion kinetics and state-of-the-art laser diagnostic and shock tube techniques. These techniques have provided, in the past, the highest quality high temperature kinetic data available and continue to be a source of reliable information.Public dissemination of this data through the web using current databases (the Kinetic Database Utilizing Shock Tube Measurements at Stanford and the PrIMe data warehouse currently located at Berkeley) will provide the public, government workers, and other researchers with the information needed to critically understand combustion processes. With one of the important problems facing Americans today being the generation of greenhouse gases from combustion processes and the subsequent effect of global warming, the proposed research is both appropriate and needed.

汉森迫切需要测量与燃烧有关的物种和反应的基本反应速率。我们高保真地模拟燃烧过程的能力依赖于对控制反应进程的一组较小的关键反应的基本反应速率的准确测量。该项目建议测量HO2与CH3、C2H5、HO2和OH反应的高温速率系数。由于反应物的高活性性质，以及开发反应物和产物浓度的定量和灵敏诊断的挑战，这些反应一直很难测量。这些反应已被认为是燃烧系统中氢过氧基浓度模拟的不确定性的主要因素。这些反应速率的测量将在高纯度激波管中进行，使用UV激光对OH、HO2、H2O2和CH3自由基的吸收以及对H2O的中红外激光吸收。被研究的温度和压力的总体范围是从800到2200K和从0.5atm到10atm。这项工作将利用最近获得的可调谐的超快(76 MHz)准连续激光系统，以便随时获得广泛的深紫外吸收跃迁和分布反馈二极管激光器的最新进展。涉及过氧化氢自由基(HO2)的智能反应在氢和碳氢化合物的氧化途径中发挥着重要作用。我们已经知道的关于这些氢过氧基反应的作用的大部分来自于较低的温度(低于800K)的实验，或来自估计。高温下这些反应的直接实验结果很少(或根本不存在)或相互矛盾，对于开发和验证燃烧动力学模型是至关重要的。为了推进这些研究，还需要开发新的和敏感的物种诊断方法。广泛影响这项研究将提供一个机会，培训新一代工程科学家现代燃烧动力学和最先进的激光诊断和激波管技术。这些技术在过去提供了现有的最高质量的高温动力学数据，并继续成为可靠信息的来源。使用当前数据库(斯坦福大学利用激波管测量的动力学数据库和目前位于伯克利的Prime数据仓库)通过网络公开传播这些数据将为公众、政府工作人员和其他研究人员提供关键地了解燃烧过程所需的信息。由于当今美国人面临的重要问题之一是燃烧过程中产生的温室气体以及随后的全球变暖影响，拟议中的研究既是适当的，也是必要的。