HF化学激光器燃烧室中燃料配比的数值分析

Numerical Study of Compositions Proportioning in Combustor of HF Chemical Laser

利用最小自由能法及质量流量守恒原则,对HF化学激光器的NF3-D2-He体系的化学平衡组分进行了计算,提出了F原子摩尔流量密度参量,分析了各输入气流的流量调节对燃烧室总温、总压、F原子产率等的影响。在燃料配比不变的情况下,总流量的增加使得F原子流量也成比例增加,而由此带来的总压升高引起的F2解离度、绝热燃烧温度、F原子摩尔分数的波动可以忽略。改变NF3流量或D2流量都可以实现对过量系数的调整。相对于改变D2流量,选择改变NF3流量能够获得更高的F原子的摩尔分数及摩尔流量密度、更小的燃烧室总压波动幅度。增加主稀释剂He的流量迅速降低了绝热燃烧温度及F原子摩尔分数,但在主稀释比小于15时仍能维持较高的F2解离度及F原子流量密度。

Chemical equilibrium compositions,total temperature and total pressure of HF chemical laser combustor for NF3-D2-He reaction system were calculated by combining minimum Gibbs＇ free energy method and mass flux conservation principle.Mole flux of F atom as a new parameter that can be used to express yield of F atom was presented.The effect of changing fuels＇ mass flow rates on combustor＇s characteristics was analyzed with emphasis.When the compositions proportion in combustor was maintained constant,increasing of mass flow rate of F atom and total pressure of combustor was in proportion to the increasing of total mass flow rate.Changing of total pressure had no obvious impact on adiabatic flame temperature,degree of F2 dissociation,and mole fraction of F atom.The changing of mass flow rates of NF3 or D2 was able to adjust the oxidizer excess factor.In comparison with changing mass flow rate of D2,changing mass flow rate of NF3 could acquire much higher mole fraction and mole flux of F atom,much smaller fluctuating amplitude of combustor＇s total pressure.Increasing mass flow rate of He decreased adiabatic flame temperature and mole fraction of F atom observably.Whereas degree of F2 dissociation and mole flux of F atom maintained a high level still when primary diluent ratio was less than 15.