水冲压发动机的热力循环性能预示

Thermodynamic cycle performance for water ramjet motors

关键词:  水冲压发动机  水燃比  热力学循环  热效率

Key words:  Water ramjet+  Water-fuel ratio+  Thermodynamic cycle  Thermal efficiency

摘要:

针对采用二次进水机制的水冲压发动机,基于特殊的工作方式初步建立了相应的热力循环模型,进而在不同的发动机工况下分析了循环热效率性能。选定水反应金属燃料基础配方为Mg/AP/HTPB的混合物,在不同组分配方条件下,相应发动机热力循环效率随各影响参数的变化规律一致,均随燃烧室压强和水反应金属燃料中金属含量的增加而呈增加趋势,相反,水燃比的增加会引起热效率的降低。特别地,给定一合理水燃比3.0,保持燃烧室压强和航行器航深分别为2.5 MPa和10 m,50%和60%镁含量的水反应金属燃料对应发动机的循环热效率分别为37.78%和44.38%,初步验证了基于联合循环的水冲压发动机良好的循环性能。

Abstract:

Toward water ramjet motors utilizing a multiple water-injection mechanism,corresponding thermodynamic cycle model has been put forwards preliminarily.Cyclic performance was also implemented under several certain working conditions.Making Mg/AP/HTPB mixture as a hydroreactive metal fuel,the rules of thermal efficiency along with some critical influential factors were obtained.In general,increasing either chamber pressure or magnesium mass fraction in basic formation fuel,thermal efficiency shows increasing trend while falling off along with water-fuel ratio.Especially,given a fair water/fuel ratio of order 3.0 while keeping the chamber pressure and navigational depth as 2.5 MPa and 10 m,respectively,thermal efficiencies were obtained as high as 37.78% and 44.38%,with respect to mass fraction of hydroreactive metal fuel with magnesium 50% and 60%,respectively.