在激波波面中氧分子的非平衡离解

对强激波作用下双原子分子振动与离解耦合的非平衡离解过程进行了理论计算.本工作的特点是将计算起点建立在分子基本参数上,采用主方程理论处理振动与离解的耦合,振动跃迁几率用SSH理论计算,在离解限附近考虑多量子数跃迁并计及原子复合的影响.对O2-Ar体系,计算给出了在正激波后O2分子振动能级分布、振动弛豫时间、离解孕育时间、离解产物浓度、离解速率系数等物理量随时间的演化.计算结果分别与Camac和Wray的实验相符.计算显示,在激波作用的后期,有准稳态的振动能级布居分布.计算结果显示,Park模型低估了非平衡离解速率系数,Hansen模型则高估了非平衡离解速率系数.

<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">A theoretical calculation is made of the nonequilibrium dissociation of the diatomic molecule with the vibration-dissociation coupling behind a strong shock wave front. The distinguishing feature of this work is to take the molecular fundamental parameters as the starting point for calculation. The master equation method is applied to study the coupling between vibrational excitation and dissociation. The vibrational transition probabilities are calculated with the SSH theory. In the neighborhood of the dissociation limit, the multi-quantum transitions are taken into account and the effect of atom recombination is considered. In a O-2-Ar mixture, the variation of many of the physical quantities of O-2 molecule behind a primary shock front with time are calculated out, such as the vibrational energy level distribution, the vibrational relaxation time, the dissociation incubation time, the dissociation product concentration and the dissociation rate coefficient. The calculated results are found to be in a good agreement with those experimental data given by Camac and Wray, respectively. It is demonstrated in the calculation that a quasi-steady state emerges at the late stage after the shock passage during which the vibrational energy level distribution persists almost constant, Park's model underestimates the nonequilibrium dissociation rate coefficient and Hansen's model overestimates the nonequilibrium dissociation rate coefficient.</span>