预混气体自由基点火的机理研究

Studies on the Mechanism of Radical Ignition of Premixed Gas

本文通过渐近理论分析研究了预混气体的自由基点火。采用包含自由基动力学的两步化学反应,基于火焰球模型,推导出了描述火焰球半径随热点火能和自由基点火能以及燃料与自由基的Lewis数的关系式。并在此基础上分别分析了不存在热点火和存在热点火时自由基点火的临界条件,研究了燃料与自由基的Lewis数对最小自由基点火能的影响。研究结果表明:仅存在自由基点火时,最小自由基点火能随着自由基Lewis数的增加而减小,但燃料Lewis数对最小自由基点火能无影响。

Asymptotic theoretical analysis is conducted to investigate the radical ignition of premixed mixtures. Considering the two-step chemistry with radical kinetics, we derive the correlation depicting the change of flame ball radius with both thermal and radical ignition power as well as the Lewis numbers of fuel and radical based on the model of stationary flame ball. With the help of this correlation, the critical conditions of radical ignition with and without thermal ignition are analyzed and the effects of fuel and radical Lewis numbers on the minimum radical ignition power are investigated. It is found that the minimum radical ignition power decreases with the radical Lewis number while it is not affected bv the fuel Lewis number.