论文标题
NOx排放以高应变速率以高应变率
NOx emissions trends in hydrogen lean premixed flamelets at high strain rate
论文作者
论文摘要
否$ _ {\ rm x} $在数值上研究了精益预处理和高度损坏的纯氢气燃料中的$。精益条件的等效比为0.7。详细的化学，一维模拟是在反应物到产品的反流配置上进行的，其应用应变速率从$ a = 100 \，{\ rm s}^{ - 1} $到$ a = 10000 \，{\ rm s}^{\ rm s}^{ - 1}^{ - 1} $}在类似的设置之后，还针对$ 2000 \，{\ rm s}^{ - 1} $和$ 5000 \，{\ rm s}^{ - 1} $的代表性应变率进行了二维直接数值模拟。两种解决方案均显示出随着施加的应变率的增加而降低的$ _ {\ rm x} $趋势。在这项研究中，对于瘦的纯净燃料燃料，首次突出显示了这种降低的排放结果。对2D解决方案的深入分析强调，在第二维中没有$ _ {\ rm x} $没有产生，因此证明了发射趋势不是设置预处理的结果，而是对火焰的直接物理效果。此外，对No $ _ {\ rm x} $形成路径的详细分析在$ a = 2000 \，{\ rm s}^{ - 1} $和$ a = 5000 \，{\ rm s}^{ - 1} $中。 Thermal no $ _ {\ rm x} $和NNH途径均显示出对总$ _ {\ rm x} $生产的贡献。虽然在不同的应变速率下，NNH路线的贡献大致恒定，但沿着热的no $ _ {\ rm x} $路由观察到显着降低。总体而言，结果表明，精益且高度良好的氢火焰经历了无$ _ {\ rm x} $的显着减少。该属性在本文中进行了讨论和分析。
NO$_{\rm x}$ formation in lean premixed and highly-strained pure hydrogen-air flamelets is investigated numerically. Lean conditions are established at an equivalence ratio of 0.7. Detailed-chemistry, one-dimensional simulations are performed on a reactants-to-products counter-flow configuration with an applied strain rate ranging from $a=100 \, {\rm s}^{-1}$ to $a=10000 \, {\rm s}^{-1}$ and the \texttt{GRI3.0} mechanism. Following a similar setup, two-dimensional direct numerical simulations are also conducted for representative strain rates of $2000 \, {\rm s}^{-1}$ and $5000 \, {\rm s}^{-1}$. Both solutions show a decreasing NO$_{\rm x}$ trend as the applied strain rate is increased. This decreasing emission outcome is highlighted for the first time in this study for lean pure-hydrogen flamelets. A deep analysis of the 2D solution underlines that there is no production of NO$_{\rm x}$ in the second dimension, thus proving that the emission trend is not a result of a setup preconditioning, but is instead a direct physical effect of stretch on the flame. Furthermore, a detailed analysis of the NO$_{\rm x}$ formation pathways at $a=2000 \, {\rm s}^{-1}$ and $a=5000 \, {\rm s}^{-1}$ is performed. Thermal NO$_{\rm x}$ and NNH pathways are shown to both contribute significantly to the total NO$_{\rm x}$ production. While the NNH route contribution is roughly constant at different strain rates, a significant decrease is observed along the thermal NO$_{\rm x}$ route. Overall, results show that lean and highly-strained hydrogen flames experience a significant decrease of NO$_{\rm x}$. This property is discussed and analysed in the paper.
