化学动力学模型对H2/AIR超燃模拟的影响

Numerical study on chemical mechanism in supersonic H2/Air mixture gas flow

关键词:  超燃冲压发动机  超声速燃烧  燃烧化学动力学  氢  反应流  数值仿真

Key words:  Supersonic combustion ramjet engine  Supersonic combustion  Combustion chemical kenetics  Hydrogen  Reacting flow  Numerical simulation

摘要:

为了研究超燃流动中不同化学反应模型的影响 ,提出流动项与化学反应生成源项解耦处理的化学非平衡流动计算方法。从薄层近似N S方程出发 ,采用ENO差分格式 ,数值模拟了超声速H2 Air预混合气体中钝体激波诱导的振荡燃烧流场 ;针对飞行速度大于和接近爆轰速度两种不同流动状态 ,比较Evans Schexnayder提出的 7组分 8反应机理 (ES模型 )、Jachimowski提出的 13组分 3 2反应机理 (J模型 )及其简化为 9组分 19反应机理 (J 1模型 )对流场参数的影响。计算表明反应机理引起压力场变化较小 ,对温度等参数影响较大。对于飞行马赫数低于7的问题 ,取不包括N原子反应的Jachimowski的 9组分 19反应机理较合适。

Abstract:

The flow of H 2/Air mixture ignited by a blund body shock was simulated numerically with an uncoupled non equilibrium method, based on N S equations and ENO scheme. The application of method was simple in structure and efficient for modifying to multi component and multi reaction chemical mechanism. The comparisons of superdetonative and transdetonative speeds were made with 7 species and 8 reactions chemical mechanism introduced by Evans and Schexnayder, 9 species and 19 reactions chemical mechanism and 13 species and 32 reactions chemical mechanism introduced by Jachimowski. The second chemical mechanism without reactions about N atom was suitable to simulate H 2/Air combustion which flight Mach number was below 7.