Experimental investigation and kinetic modelling of NO formation at elevated pressures using laser diagnostic in a Rapid Compression Machine

在快速压缩机中使用激光诊断在高压下形成 NO 的实验研究和动力学建模

• 批准号: 418305555
• 负责人: Professor Dr.-Ing. Alexander Heufer
• 金额: --
• 依托单位: Lehrstuhl für Technische Thermodynamik (LTT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/418305555?language=en
• 关键词: Experimental; investigation; kinetic; modelling; NO

Reducing pollutant emissions in combustion processes is one of the major challenges worldwide. In this context not only the overall greenhouse gas emissions but also the local release of pollutants is of high relevance. For tackling this problem a detailed understanding of the combustion and the pollutant formation kinetics is necessary in order to understand and model its mechanisms. Only by this appropriate counter measures can be developed.As a consequence this proposal aims to investigate the reaction mechanism of nitrous oxide using a combination of theoretical and experimental approach. On the theoretical side kinetic models will be optimized based on literature information and data resulting from this project. A special focus will be on the low temperature reaction scheme since currently available models show a large scatter in the predictions in this temperature regime. On the experimental side investigations of fuel-air mixtures doped with nitrous oxide in a rapid compression machine (RCM) will deliver new information. Besides conventional ignition delay time measurements, one-dimensional quantitative nonintrusive NO concentration and temperature measurements will be conducted in the early-cycle combustion process in the RCM. Spatial resolution of the diagnostic is required because of temperature gradients in the charge. Thus, the proposed diagnostic is based on spontaneous Raman scattering (SRS) and laser-induced fluorescence (LIF). While LIF yields the local NO concentration with high sensitivity, SRS will be applied to measure light attenuation and temperature. These latter quantities are the two most important factors required for quantification of NO-LIF. Calibration of both NO-LIF and SRS will be performed at the end of compression in the RCM. SRS diagnostics are based on nitrogen. The temperature will be inferred from the spectral band shape of Stokes N2-SRS, whereas anti-Stokes N2-SRS will yield attenuation spectrally very close to an attractive NO-LIF emission wavelength (~ 236 nm). This type of combined SRS/LIF diagnostic was recently developed by the applicants at the LTT for automotive combusting fuel jets in a high-pressure vessel. In the currently proposed first half of the project, the most important research question for the LTT will be whether that (slightly modified) diagnostic can be applied to the discussed combustion processes in the RCM and whether the resulting measurement uncertainties are at least as low as in those previous works. The potential and limitations of this diagnostic in the current environment will be investigated. Complete quantification of NO-LIF will be conducted for a few selected operating conditions of the RCM in the first half of the project. The results of that first half will be used for planning the second half, in which a larger number of NO-LIF measurements will be conducted for various operating conditions.

减少燃烧过程中的污染物排放是全球面临的主要挑战之一。在这方面，不仅温室气体的总排放量，而且当地污染物的排放量都具有高度的相关性。为了解决这个问题，有必要详细了解燃烧和污染物形成动力学，以便了解其机制并对其进行建模。因此，本研究旨在从理论与实验相结合的角度探讨氧化亚氮的反应机理。在理论方面，动力学模型将根据本项目的文献信息和数据进行优化。一个特别的重点将是在低温反应计划，因为目前可用的模型显示在这个温度制度的预测很大的分散。在实验方面，在快速压缩机（RCM）中对掺有一氧化二氮的燃料-空气混合物的研究将提供新的信息。除了常规的点火延迟时间测量，一维定量非侵入NO浓度和温度测量将在燃烧过程的早期循环在RCM进行。由于装料中的温度梯度，需要诊断的空间分辨率。因此，所提出的诊断是基于自发拉曼散射（SRS）和激光诱导荧光（LIF）。激光诱导荧光产生的局部NO浓度具有很高的灵敏度，而受激喇曼散射将被应用于测量光衰减和温度。后两个量是NO-LIF定量所需的两个最重要的因素。将在RCM中压缩结束时对NO-LIF和SRS进行校准。SRS诊断基于氮气。温度将从斯托克斯N2-SRS的光谱带形状推断，而反斯托克斯N2-SRS将产生非常接近有吸引力的NO-LIF发射波长（~ 236 nm）的光谱衰减。这种类型的组合SRS/LIF诊断最近由申请人在LTT开发，用于高压容器中的汽车燃烧燃料喷射。在目前提出的项目的前半部分，最重要的研究问题的LTT将是（略有修改）诊断是否可以应用到所讨论的燃烧过程中的RCM和所产生的测量不确定性是否至少是低的，因为在这些以前的工作。在当前的环境中，这种诊断的潜力和局限性将进行调查。在项目的前半部分，将对RCM的一些选定操作条件进行NO-LIF的完全量化。前半部分的结果将用于规划后半部分，其中将针对各种操作条件进行大量的NO-LIF测量。