甲烷-湿空气对冲扩散火焰中CO的生成特性

THE CHARACTERISTICS OF CO EMISSION IN METHANE-HUMID AIR COUNTERFLOW DIFFUSION FLAME

本文描述了HAT循环中CO排放的基础研究结果。为了澄清加湿和CO排放的关系,采用GRI-mech3．0详细化学反应机理,对甲烷-湿空气对冲扩散火焰进行了数值研究。对不同的空气含湿量通过改变进口预热温度调节最高火焰温度,解耦湿空气影响火焰的温度和自由基浓度效应,研究甲烷-湿空气火焰中CO生成的化学机理。计算结果表明在火焰最高温度相同的情况下,湿空气中的水蒸汽使OH基浓度增加、O基和H基浓度降低,从而抑制CO的生成。这些结果有益于准确预测HAT循环中CO的排放。

This paper presents the results of fundamental research on CO emissions in HAT cycle. To clarify the relationship between H2O and CO emissions, the characteristics of methane-humid air counterfiow diffusion flame have been simulated numerically by applying GRI-Mech 3.0 detail chemical kinetics. To investigate the chemical reaction effects of steam addition on the CO formation with the effect of the temperature decrease because of steam addition excluded, the maximum flame temperature was adjusted to the same value by varying the initial temperatures. The calculated results clearly show that with steam addition, the OH radical is increased, O radical and H radical is decreased for the same flame temperature. So the production rate of CO is decreased. These results may be useful to predict CO emissions in HAT cycle.