Abstract Advanced combustion technologies to limit NOX production are needed to meet rigorous emissions standards, which are required due to the harmful effect of NOX on the environment. One such advanced concept involves axially staging the fuel to create a staged combustion system. This paper reports on emissions measurements obtained for premixed natural gas and air reacting jets into vitiated crossflow with negligible swirl at conditions corresponding to elevated inlet temperatures of 500–600 K and an elevated combustor pressure of 500 kPa. A significant NOX reduction was achieved when the staged combustor exit Mach number was increased and the axial residence time was reduced. Based on this preliminary investigation, a test matrix was developed to independently vary the exit Mach number for a constant axial residence time by utilizing modular rig hardware to change the length of the axial combustor. Up to 70% reduction in NOX produced by the axial stage was observed when the combustor exit Mach number was increased from about 0.26 to 0.66 at a constant residence time of 1.4 ms. NOX reduction based on variation in the Mach number and at a constant residence time has not been previously reported in the literature to the best of our knowledge. This decrease in NOX is hypothesized to be due to the lower static temperature of a compressible flow and potentially better mixing of the jet with the crossflow due to the interaction occurring at high speeds. The effects of axial residence times on NOX emissions were also investigated at a constant Mach number of 0.44 for axial residence times between 0.8 and 2.3 ms. Varying the axial residence time was observed to have a strong effect on NOX emissions for exit total temperatures greater than 1900 K, which agrees well with existing trends.

中文翻译：

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通过增加燃烧器出口马赫数减​​少轴向分级燃气轮机模型燃烧器中的 NOX

摘要 由于氮氧化物对环境的有害影响，需要采用先进的燃烧技术来限制氮氧化物的产生，以满足严格的排放标准。一个这样的先进概念涉及轴向分级燃料以创建分级燃烧系统。本文报告了在入口温度升高 500-600 K 和燃烧室压力升高 500 kPa 的条件下，预混天然气和空气反应射流进入带有可忽略的涡流的有缺陷的交叉流中获得的排放测量值。当分级燃烧器出口马赫数增加和轴向停留时间减少时，NOX 显着减少。根据这项初步调查，开发了一个测试矩阵，通过利用模块化钻机硬件改变轴向燃烧器的长度，独立地改变出口马赫数以获得恒定的轴向停留时间。当燃烧器出口马赫数从大约 0.26 增加到 0.66 且停留时间为 1.4 ms 时，观察到轴向级产生的 NOX 减少高达 70%。据我们所知，基于马赫数变化和恒定停留时间的 NOX 减少以前没有在文献中报道过。假设 NOX 的减少是由于可压缩流的静态温度较低，并且由于高速发生的相互作用，射流与横流可能更好地混合。还在恒定马赫数 0 下研究了轴向停留时间对 NOX 排放的影响。44 轴向停留时间在 0.8 和 2.3 毫秒之间。观察到改变轴向停留时间对出口总温度大于 1900 K 的 NOX 排放有很大影响，这与现有趋势非常吻合。