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主要挑战之一。在这种情况下，不仅是整体温室气体排放，而且污染物的本地发行都具有很高的相关性。为了解决此问题，必须详细了解燃烧和污染物形成动力学，以了解和建模其机制。只有通过这种适当的反应措施才能开发出来。因此，该提案旨在使用理论和实验方法的结合来研究一氧化二氮的反应机制。在理论方面，动力学模型将根据该项目产生的文献信息和数据进行优化。由于当前可用的模型在该温度状态的预测中显示出大量散布，因此将特别关注低温反应方案。在快速压缩机（RCM）中用一氧化二氮掺杂的燃料空气混合物的实验侧研究将提供新的信息。除了常规的点火延迟时间测量外，在RCM的早期周期燃烧过程中将进行一维定量非浓度和温度测量。由于电荷中的温度梯度，需要进行诊断的空间分辨率。因此，提出的诊断基于自发的拉曼散射（SRS）和激光诱导的荧光（LIF）。尽管LIF产生具有高灵敏度的局部无浓度，但SR将应用于测量光衰减和温度。这些后一个数量是量化无LIF所需的两个最重要的因素。在RCM的压缩结束时，将执行NO-LIF和SRS的校准。 SRS诊断基于氮。温度将从Stokes N2-SR的光谱带形状推断出来，而抗Stokes N2-SRS将在光谱上产生衰减，非常接近有吸引力的无液发射波长（〜236 nm）。申请人最近在LTT上开发了这种类型的SRS/LIF诊断，用于高压容器中的汽车燃烧燃料喷射。在该项目的当前提议的上半年中，有限元的最重要的研究问题是（稍微修改）诊断是否可以应用于RCM中讨论的燃烧过程，以及所得的测量不确定性是否至少与以前的作品相当。将研究此诊断在当前环境中的潜力和局限性。在项目上半年，将对RCM的一些选定操作条件进行完全量化。该上半场的结果将用于计划下半年，其中将针对各种操作条件进行大量的无运行测量。