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。在这种情况下，不仅总体温室气体排放，而且当地污染物的释放也具有高度相关性。为了解决这一问题，有必要详细了解燃烧和污染物形成动力学，以便理解和模拟其机制。只有这样，才能制定适当的对策。因此，本研究旨在采用理论和实验相结合的方法研究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。特别的重点将放在低温反应方案上，因为目前可用的模型在这种温度状态下的预测中显示出很大的分散。在实验方面，在快速压缩机（RCM）中研究掺有一氧化二氮的燃料-空气混合物将提供新的信息。除了常规的点火延迟时间测量外，还将在RCM的早循环燃烧过程中进行一维定量非侵入式NO浓度和温度测量。由于电荷中的温度梯度，需要诊断的空间分辨率。因此，提出的诊断是基于自发拉曼散射（SRS）和激光诱导荧光（LIF）。LIF以高灵敏度获得局部NO浓度，而SRS将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。NO-LIF和SRS的校准将在RCM压缩结束时进行。SRS诊断是基于氮的。温度将从Stokes N2-SRS的光谱带形状推断，而反Stokes 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SRS/LIF组合诊断是由LTT的申请人最近开发的，用于高压容器中的汽车燃烧燃料射流。在目前提出的项目的前半部分，LTT最重要的研究问题将是（稍微修改的）诊断是否可以应用于RCM中讨论的燃烧过程，以及由此产生的测量不确定度是否至少与以前的工作一样低。在当前环境下，将研究这种诊断的潜力和局限性。在项目的前半部分，将对RCM的几个选定的操作条件进行NO-LIF的完整量化。上半年的结果将用于计划下半年，其中将针对各种操作条件进行更多的NO-LIF测量。