喷嘴结构和射流参数对射流预冷温度特性的影响

Effect of nozzle structure and jet parameters on the temperaturecharacteristics of mass injection and pre-compressor cooling

航空发动机进气温度过高是限制其性能的关键问题之一,采用射流预冷技术可以有效降低航空发动机进气温度。为了研究射流预冷技术对进气道内温度场的影响,基于欧拉-拉格朗日方法,建立航空发动机进气道液滴雾化和蒸发过程的数学模型,实现气液两相的双向耦合,描述了射流预冷过程。并与已有的试验结果进行对比,验证了数学模型的准确性。并利用该数学模型研究了水气比、喷射速度、液滴粒径和喷嘴锥角对进气道降温效果和温度畸变的影响。结果表明:改变水气比发动机进气温度变化最显著,当水气比由0.02增大至0.055时,温降系数由8.10%增加到19.87%,蒸发率由85.76%降低为79.80%;当水气比为0.055、喷射速度为10 m/s、液滴粒径为25μm和喷嘴锥角为15°时,温降系数最大为22.77%;增大喷嘴锥角和减小喷射速度会使进气道出口截面温度场分布更均匀。

Excessive high intake temperature is one of the key problems limiting the performance of aero-engines,mass injection and pre-compressor cooling(MIPCC)technology can effectively reduce the intake temperature of aero-engine.In order to investigate the influence of MIPCC technology on the temperature field in the inlet,a mathematical model of the droplet atomization and evaporation process was established.Based on Euler-Lagrange method,the mathematical model was used to realize the twoway coupling of the gas-liquid two-phase and describe the MIPCC process in the intake port of an aeroengine.Compared with the existing test results,the accuracy of the mathematical model was verified.The effects of water-air ratio,injection velocity,particle diameter and nozzle cone angle on the cooling effect and temperature distribution of the inlet were studied by using the mathematical model.The results showed that when the water-air ratio increased from 0.02 to 0.055,the cooling ratio increased from 8.10%to 19.87%,and the evaporation rate decreased from 85.76%to 79.80%;when the water-air ratio was 0.055,the injection velocity was 10 m/s,the droplet size was 25μm and the nozzle cone angle was 15°,the maximum temperature drop coefficient was 22.77%.Increasing the nozzle cone angle and decreasing the injection velocity made the temperature field distribution in the outlet section of the inlet more uniform.