凹腔底壁喷射位置的数值模拟与试验

Experimental and Computational Study of Injection Positions in Cavity Flame Holder

关键词:  超燃冲压发动机  超声速燃烧  凹腔火焰稳定器  气泡雾化  试验研究

Key words:  Scramjet  Supersonic combustion  Cavity flame holder  Effervescent atomization  Experimental study

摘要:

为探究凹腔底壁不同喷射位置对碳氢燃料的燃烧性能的影响,在直联式超燃试验台上进行了凹腔底壁不同喷射位置的气态燃料(乙烯)、液态燃料(煤油)以及气泡雾化煤油(起泡气体为氢气、空气、氮气)的超声速燃烧试验。并针对凹腔底壁不同位置喷乙烯进行了数值仿真。通过分析燃烧室壁面压力与数值模拟结果得到:凹腔底壁不同喷射位置对气态燃料的点火性能影响不大,燃烧性能随喷点位置的后移下降。煤油通过靠近凹腔前缘的喷孔喷入可顺利点火,而通过靠近后缘的喷孔无法实现点火。应用氢气作为起泡气体的气泡雾化喷嘴后,实现了所有喷点的点火,但随着喷点位置的后移,煤油的燃烧性能下降。

Abstract:

Experimental investigation of supersonic combustion, using gaseous fuel (ethylene), liquid fuel (kerosene), and effervescent atomization kerosene (effervescent gas used hydrogen, air, and nitrogen), in different injection positions in the bottom wall of cavity flame holder was performed on direct-connect supersonic combustion test facility to study the effects of different positions in cavity on combustion. Computation for different injection positions of ethylene has been carried out. The results of experiment and computation indicate that different injection positions for ethylene in cavity bottom wall have no obvious effects on ignition, but combustion performance falls when injection position moving downstream. Successful ignition could be obtained by using direct injection of liquid kerosene through the most upstream hole in cavity, while not using the downstream holes. After using effervescent atomization with hydrogen as the effervescent gas, we realized the kerosene ignition at all injection positions, but the combustion performance falls when the injection position moving downstream.