油气比对超燃发动机点火过程的影响  

Influence of Fuel-Air Ratio on Scramjet Ignition

作　　者：王西耀[1,2] 杨顺华[1,2] 乐嘉陵[1,2] 

机构地区：[1]中国空气动力研究与发展中心高超声速冲压发动机技术重点实验室,四川绵阳621000 [2]中国空气动力研究与发展中心吸气式高超声速技术研究中心,四川绵阳621000

出　　处：《推进技术》2012年第4期522-529,共8页Journal of Propulsion Technology

摘　　要：为了研究油气比对超燃发动机自点火性能的影响,利用二维非定常化学非平衡计算方法模拟了总温2000K,总压3.0MPa,入口马赫数3.0,煤油油气比为0.2和1.0时超燃发动机的自点火过程。具体可以得到以下结论:(1)总油气比越高,燃料传播速度越快;燃料首先沿着剪切层传播至凹槽后缘,之后在凹槽漩涡的带动下向凹槽上游和底部传播。(2)凹槽回流区温度高,点火延迟时间短,低油气比的气体一旦进入凹槽回流区后即可在凹槽后缘和上方点火。(3)火焰从凹槽的上沿和右边向凹槽底部和左边传播。(4)总油气比越高,点火越困难。To study the influence of fuel-air ratio on the scramjet self-ignition, two self-ignition processes of kerosene fu- eled scramjct were simulated with 2D non-equilibrium unsteady numerical method, the total temperature, total pressure and Mach number of the incoming flow were 200OK, 3. OMPa and 3.0 respectively, the two cases had different fuel-air ratios, one was 1.0 and the other 0.2. Four conclusions can be reached. Firstly, the higher the fuel-air ratio is, the faster the fuel propa- gates; fuel propagates through the shear layer downstream first, and when achieving the rear cavity wall, kerosene will be propagated to the cavity upstream and bottom by the vortices. Secondly, the temperature in the cavity is high, so the ignition delay time is short, and as soon as the mixed gas with lower fuel-air ratio propagates into the cavity the ignition will occur downward and upward in the cavity. Thirdly, the flame propagates from top and right to bottom and left in the cavity. Fourthly, the higher the fuel-air ratio is, the more difficult the ignition is.

关 键 词：超燃冲压发动机 自点火 非定常计算 化学非平衡 点火延迟时间 

分 类 号：V235.21[航空宇航科学与技术—航空宇航推进理论与工程]