富氢燃气与空气低压补燃特性研究
杨进慧,王朝晖,田 原,许晓勇

(北京航天动力研究所, 北京 100076)

富氢燃气; 低压补燃; 化学反应速率; 富氢燃气温度; 富氢燃气组分

Research on recombustion properties of hydrogen-rich gas with air at sub-atmospheric pressure
YANG Jinhui, WANG Zhaohui, TIAN Yuan, XU Xiaoyong

(Beijing Aerospace Propulsion Institute, Beijing 100076, China)

hydrogen-rich gas; recombustion at sub-atmospheric pressure; reaction rate; hydrogen-rich gas temperature; hydrogen-rich gas component

备注

氢氧火箭发动机在飞行过程中排出富氢燃气与周围低压空气发生补燃,直接改变发动机周围的热环境,影响发动机各组件性能。通过试验及仿真研究了不同燃气温度、燃气组分对于富氢燃气低压补燃特性的影响。富氢燃气与空气的低压补燃试验表明:常压下富氢燃气温度高于932 K时发生补燃,低于877 K时不发生补燃; 富氢燃气温度高于950 K,环境压力60 kPa时富氢燃气发生补燃,30 kPa时不发生补燃; 仿真与试验对比分析发现最大化学反应速率超过10-9情况下能观测到宏观的富氢燃气与空气的补燃现象,燃气温度和氢气含量越高,其与空气发生补燃的临界压力越低。当压力低于10 kPa时,燃气温度1 200 K,氢气含量87.4%也无法与空气发生补燃。

The hydrogen-rich exhaust gas from the hydrogen-oxygen rocket engine recombustion with surrounding low-pressure air, which directly changes the thermal environment of engine and will be destructive to the engine components performance. Experiments and simulation were conducted to study the effects of different hydrogen-enriched gas temperature and component on the flammability limit of hydrogen-rich gas with air at sub-atmospheric pressures. Flame can be observed when the gas temperature was higher than 932 K at atmospheric pressure, and no flame when gas temperature lower than 877K. The 950 K hydrogen-rich gas will recombust with air when environment pressure is higher than 60 kPa, and there is no reaction when the pressure below 30 kPa. According to the flammability simulation results, recombustion can be observed when the reaction rate exceeds 10-9. Simulation results indicate that the hydrogen-rich gas flammability pressure limit reduce with higher gas temperature and hydrogen ratio. As environment pressure lower than 10 kPa, the 1200 K gas which consists of 87.4% hydrogen could not recombust with air.