阴燃转捩为明火燃烧的分岔特性及气相反应临界状态消失分析

Application of bifurcation tieory in transition from smoldering to flaming of fuel

通过理论分析研究了燃料阴燃着火-熄火及向明火转捩的分岔特性。以1β为控制参数对燃料阴燃着火-熄火及向明火转捩的发生进行了的分岔分析。计算表明:分岔曲线明显地分为固相着火区和气相着火区,整个变化过程呈现出二次分岔特点。通过气相反应临界状态消失分析可知:2ε=0.05是气相反应的分岔曲线临界状态消失的转变点,2ε值越大,燃料在阴燃越容易发生气相反应,但温度降低;2α=0.53也是气相反应临界状态的一个转变点,2α越大气相反应的温度越接近于固相阴燃温度,而且当α2→+∞时,只有固相阴燃反应存在而不会发生气相反应。

Based on the theoretical analysis, the bifurcation characteristics of the ignition-extinction of solid-phase smoldering and transition to flaming were studied. One of the Frank-Kamenetskii parameter β1 was selected as the control parameter. The ignition-extinction of solid-phase smoldering and gas-phase reaction was numerically analyzed. The computational results show that the bifurcation curve is obviously divided into two zones of solid-phase reaction and gas--phase reaction, and the total process of ignition-extinction presents the second bifurcation characteristic. Moreover, the vanishing of critical state of ignition-extinction was studied. One of the transition points, ε2 = 0.05 , was numerically solved for the vanishing of critical state. The larger the value of ε2 is, the easier the gas-phase can react. However, the combustion temperature will decrease with increasing ε2. The other transition point α2=0. 53 was also obtained. With increasing the value of α2, the combustion temperature of gas-phase reaction is close to the smoldering temperature of fuel. When α2 is infinite, the only reaction occurring is the smoldering combustion of solid-phase, and the gas-phase cannot react.