涡轮级间燃油雾化特性数值研究

关键词:煤油；雾化；加力燃烧室；数值模拟

关键词:  煤油  雾化  加力燃烧室  数值模拟

Key words:  Kerosene  Atomization  Afterburner  Numerical simulation

摘要:

为实现航空发动机加力燃烧室的无稳定器燃烧组织，以加力燃烧室燃油在涡轮内提前雾化蒸发特性为研究对象，采用经过试验验证的数值模拟方法，对燃油喷雾在涡轮级内的流动雾化特性及影响因素开展数值分析。在不同来流温度条件下，考察了燃油在静子流道的展向、周向和轴向不同喷入位置的运动轨迹、粒径分布和涡轮出口气态燃油浓度分布。研究结果表明，喷雾位置和来流总温对燃油雾化特性都存在影响，具体表现在:(1)不同展向位置的燃油雾化特性相似；(2)吸力面燃油雾化质量优于压力面；(3)在喉道附近的燃油雾化质量优于叶片前缘和尾缘；(4)在雾化过程中的不同时段，液滴数量的变化是破碎与蒸发的竞争机制影响的结果；(5)提高来流总温可以提高雾化质量。另外，涡轮内非均匀流场中各位置温度与速度对燃油雾化蒸发影响的比重不同，在同一来流总温条件下，速度对燃油雾化的影响大于温度。

Abstract:

In order to organize combustion in the aeroengine afterburner without stabilizer， a numerical simulation method verified by experiments was used to study the advance atomization and evaporation of fuel of the afterburner in the turbine stage. The flow characteristics， atomization characteristics and influence factors of fuel spray in the turbine stage were analyzed in detail. Jet fuel was injected into the stator stage at different spanwise， circumferential and axial positions. The trajectory of fuel spray， the particle size distribution and the distribution of gas fuel concentration in the turbine outlet were investigated under different flow temperature conditions. The results show that the fuel injection position and airflow total temperature have a great influence on the atomization in the turbine stage. The atomization characteristics of fuel at different spanwise positions are similar. The atomization quality of the fuel around the suction surface is better than that around the pressure surface. The quality of fuel atomization near the throat is superior to that near the leading edge and trailing edge of the blade. In different periods of the atomization process， droplet number change is the result of the competition mechanism between pneumatic breakage and evaporation. The increase of total temperature of the airflow can increase the atomization quality. In addition， in the inhomogeneous flow field in the turbine， the proportion of the influence of temperature and speed on fuel atomization and evaporation changes because of different fuel injection positions. For the conditions tested， the effects of velocity on the atomization of fuel are greater than those of the temperature in the same airflow total temperature.