脉冲风洞发动机试验多油位多时序高精度燃料供应系统

High precision fuel supply system with multi-scheduling for multi-fuel-supplypipelines used for scramjet test in pulse wind tunnel

针对脉冲风洞超燃冲压发动机试验要求燃料供应快速、稳定、精确的特点,设计了一套燃料供应系统,可多油位多时序高精度地实现试验模型燃料供应、模型点火器气源供应、气体节流气源供应等功能。该系统供应的燃料为乙烯、甲烷、氢气及其混合物。采用压力补偿装置,保持燃料稳定供应,实现燃料当量比精确控制。设计了由电磁阀和气动阀组合而成的快速供气阀门,阀门开启时间小于20ms,关闭时间小于30ms,实现燃料的安全、快速供应。对超燃发动机模型不同油位设计了专门的供油回路,通过电磁阀控制系统,实现多个油位不同时序的控制动作,时序控制精度达到1ms。给出了详细的系统设计回路,并对关键部件参数进行了计算。点火试验表明该系统可以为点火器提供稳定的空气和氢气,点火器正常时间超过500ms。在脉冲式直连式试验台上,进行了乙烯燃料超燃发动机试验,对该套供油系统进行了测试。试验监控了供油管道及模型壁面的压力分布,供油压力在试验时间内波动小于3%,发动机壁面压力显示燃烧性能良好。空气节流试验表明,该系统提供的时长为100ms、压力为4.7MPa的节流空气成功点燃了乙烯。

Scramjet tests in pulse wind tunnel require fuel supply system working quickly, steadily and accurately. To satisfy these requests, an integrated high precision fuel supply system with multi- scheduling for multi-fuel-supply-pipelines is established. Its functions include fuel supplying to scramjet model, air and hydrogen supplying to igniter and air supplying for throttling. The fuel supplied by this system is ethylene, methane, hydrogen and their mixture （a surrogate for endothermically-cracked J P- 7）. A pressure-compensation device is employed to hold fuel supply pressure steady, thereby making the fuel/air mass ratio exact. The fuel feed valve composed by electromagnetic valve and pneumatic imple- ment can safely distribute fuel in the designed period of time. The valve needs less than 20ms and 30ms to turn on and turn off respectively. For different scramjet fueling schemes, multi-fuel-pipelines with multi scheduling are designed and controlled by electromagnetic valve. The timing precision for fueling control can reach to the level of lms. In this paper, detailed fuel and gas loops in this integrated system are presented. Also the parameters of key components are computed. Ignition, combustion and air-throt- tling experiments are carried out to check the performance of the system. The results show that the sys- tem can supply air and hydrogen to the igniter as long as 500ms, exceeding the time needed for scramjet direct-connect test. The combustion capability of an ethylene fueled scramjet model is investigated. The monitored pressures of fuel supply pipelines fluctuate less than 3 %. Also the pressure-steady air supplied by the system for lOOms throttling ignites ethylene successfully.