绝热逆向阴燃波的热扩散不稳定性

Diffusive-thermal instability of adiabatic reverse smolder waves

通过数值方法研究在绝热条件下逆向阴燃的热扩散不稳定性以及失稳后的非线性发展过程.通过正则模态分析方法研究绝热逆向阴燃的线性稳定性,得到以氧气Lewis数和气体流量Mg表征的线性稳定性图谱.结果表明,绝热逆向阴燃随控制参数的变化存在两种不同特征的不稳定性,即元胞(或指状)不稳定性和行波不稳定性,对阴燃波二维非线性失稳过程的模拟印证了这一线性稳定性分析结果.

We employ numerical strategies to investigate the diffusive-thermal instability of adiabatic reverse smolder waves and the subsequent evolution processes of the smolder waves following the onset of instability.First,the linear stability of adiabatic reverse smolder waves is assessed using the numerical normal mode analysis method.This analysis generates a stability diagram characterized by the oxygen Lewis number and the incoming air flow rate Mg.Two different types of instabilities are identified:cellular(or fingering)instability and traveling wave instability.The categorization depends on the range of the control parameters.The linear stability analysis results are validated through a comparison with numerical simulations of 2-D nonlinear evolution processes of smolder waves.