高温非平衡氮组分多温度振动-离解耦合模型

 基于多温度模型的基本思想,从惟象角度分析了非平衡状态下双原子分子振动态分布的特征信息。研究了双原子分子在非平衡弛豫过程中振动—离解耦合特点,认为较低和较高振动态首先达到相对独立的准平衡状态,较高振动态的局域离解造成的相对数密度分布密度差将导致各个振动态数密度从新分布;而这一过程也是系统通过V-V传能、T-V传能不断把位于较低振动态的分子通过中间振动态激发到较高振动态,为离解做能量积累的过程。通过对目前较常用的Hammerling假设的修正,用中间振动态数密度分布情况重新定义了双原子分子非平衡态下的振动温度,建立了新的关联振动-平动温度的双原子分子振动态非平衡近似分布模型。通过模拟氮分子非平衡激波加热过程结果表明,本模型较好地预报了氮分子非平衡振动松弛过程中"诱导期"以及平均振动能、振动温度的时间特性。

Multi-Temperature Coupled-Vibration-Dissociation Model of High-Temperature Nonequilibrium Nitrogen Species

In this paper,based on the idea of the multi-temperature model,the characteristic information of distribution of vibrational levels is phenomenologically analyzed and the vibration-dissociation coupling characteristics of diatomic molecules in nonequilibrium relaxing process are also investigated.It is found that the lower and higher vibrational levels of diatomic molecule could reach an independently quasi-equilibrium relatively fast,but the relative population density difference between the vibrational levels,which caused by the partially dissociation of the higher levels,could lead to the redistribution of all vibrational levels.And this redistribution process is also a cumulating energy process for dissociation in which the molecules of the lower levels would be excited to the higher levels through the mid-vibrational levels by vibrational-vibrational and translational-vibrational energy exchange in sequence.By modifying the Hammerling hypothesis,the vibrational temperature are redefined by the distribution of mid-levels of vibration,and a new correlated vibrational and translational temperatures model of diatomic molecular vibrational levels population distribution in thermodynamic nonequilibrium states is built.The simulation results of the nonequilibrium nitrogen species relaxation process behind a shock wave show that this model can predict the incubation period and the relaxation time characteristic of average vibrational energy and vibrational temperature.