喷水射流预冷对加力燃烧室特性影响分析

Effects Analysis of Water Spray Mass Injection Pre-Compressor Cooling on Afterburner Characteristics

关键词:  射流预冷  气液两相流  预冷特性  燃烧效率  蒸发率

Key words:  Mass injection and pre-compressor cooling  Gas-liquid two-phase flow  Pre-cooling characteristics  Combustion efficiency  Evaporation rate

摘要:

为了探究采用射流预冷技术之后加力燃烧室性能，开展了不同喷嘴布置方案、喷水量和来流温度对预冷效果的影响研究。对射流预冷发动机工作过程进行了简化，建立了加力燃烧室进口前段射流预冷喷水特性计算的数学模型。同时搭建了小型试验台，通过与试验结果的比对验证了该模型的准确性，并利用该模型对射流预冷效果进行了仿真预测。结果表明：提高喷嘴数量与布置均匀性能够小幅度改善预冷效果；当来流温度不变时，射流预冷喷射腔室出口处的液态水蒸发量随着喷水量的增加而提高，但蒸发率却处于下降的趋势；当喷水量达到2%时，加力燃烧室燃烧效率对比不喷水工况会有一定的提升；喷水量达到4%以后，加力燃烧室出口温度及燃烧效率随着喷水量的提高而降低；喷水量大于8%以后，恶化了加力燃烧室（V型火焰稳定器）贫油熄火极限与燃烧效率；喷水量达到最大10%时，油气比需从原来设计工况的0.052上升到0.064才能保持稳定点火且对比不喷水时工况，加力燃烧室出口温度由1860K下降到1373K，燃烧效率由80.2%下降到69.2%。

Abstract:

In order to investigate the combustion performance of afterburner after adopting the Mass Injection and Pre-Compressor Cooling （MIPCC） technology， the effects of different nozzle layout schemes， water spray volumes and incoming flow temperatures on pre-cooling effect were studied. The working procedures of MIPCC engine was simplified， and a mathematical model to calculate the water spray characteristics of MIPCC in the inlet front section of the afterburner was established. Simultaneously， a small-scale test bench for MIPCC was also set up. The accuracy of the model has been verified by comparing with the test results， and the model was also used to predict the effect of MIPCC. The results showed that increasing the number and arrangement uniformity of the nozzles can slightly improve the pre-cooling effect. At the fixed inlet temperature， the liquid water evaporation at outlet increased gradually with the increase of the water spray volume， but the evaporation rate was in a decline trend. When the volume of water spray reached 2%， the combustion efficiency of afterburner showed a prominent improvement compared with that without water spray. After the water spray volume reached 4%， the outlet temperature and combustion efficiency of afterburner decreased with the increase of water spray volume. With the water spray volume over 8%， the lean oil flameout limit and combustion efficiency of afterburner（V-gutter flameholder）become deteriorated obviously， When the water spray volume reached the maximum value of 10%， the oil-gas ratio rise from the original value of 0.052 to 0.064 to maintain stable ignition. Meanwhile， the outlet temperature of afterburner decreased from 1860K to 1373K， and the combustion efficiency would decrease from 80.2% to 69.2% compared with the working condition without water spray.