喷水射流预冷对发动机进气温度及流场变化影响的数值研究

Numerical Study on Effects of Water Injection Pre-Compressor Cooling on Engine Inlet Temperature and Flow Field Change

关键词:  射流预冷  预冷段  流场特性  高温  蒸发

Key words:  Mass injection and pre-compressor cooling  Cooling section  Flow field characteristic  High temperature  Evaporation

摘要:

射流预冷技术可以有效降低进气温度并提高航空发动机的性能。为探究该技术在高空环境下对流场问题的影响，采用径向均匀射流方案，模拟高空条件，结合水滴的蒸发过程以及气液两相的耦合作用对预冷段射流喷水的情形进行数值计算。结果表明，径向喷射方案能够有效降低进气温度，在各个工况中，温降系数约为8%~26.7%；在高温工况中提高喷水量可以有效提高温降效果，工况6的喷水量和工作温度都是最大的，温降系数和蒸发效率分别达到了最高值的26.7%和73.9%；预冷段的压降损失和出口流场均匀度取决于来流马赫数和喷水量，高马赫数和较大的喷水量都会加剧压损与流场的紊乱程度，由于工况6的高射流量和气流马赫数，其在喷水装置处的压降系数达到了最大值的5.8%。

Abstract:

Mass Injection and Pre-Compressor Cooling (MIPCC) technology has influence on reducing temperature of inlet air to improve the engine performance. In order to explore the effect of technology on the field at high altitude environments, the radial even spray arrangement is adopted to simulate altitude conditions to investigate air/droplet fully coupled cooling and evaporation of water in the cooling section with numerical study. The results indicate that the temperature of inlet air is effectively reduced by the radial arrangement of nozzles. Values of temperature drop coefficient can achieve 8%~26.7% among cases. Then, it is a better method to reduce the temperature of inlet air by raising the injection flow at higher operating temperature. The temperature drop coefficient and evaporation efficiency can achieve the largest value of 26.7% and 73.9% for case 6 with higher injection rate and temperature of inlet air. Moreover, larger amount of the injection flow and inlet air at higher Mach number will deteriorate the total pressure loss and the flow field uniformity, the total pressure drop coefficient gets the largest value of 5.8% at the location of spray system for case 6 with largest injection rate and highest Mach number of inlet air.