径向非均匀进气喷湿对跨声速压气机气动性能影响研究

Effects of Radial Non-Uniform Inlet Fogging on Aerodynamic Performance of Transonic Compressor

关键词:  跨声速压气机  径向非均匀喷雾  湿压缩  气动性能  数值模拟

Key words:  Transonic compressor  Radial non-uniform fogging  Wet compression  Aerodynamic performance  Numerical simulation

摘要:

针对湿压缩技术的应用，为了深入认识径向非均匀进气喷湿对压气机气动性能的影响，以某跨声速压气机级为研究对象，采用CFD技术结合欧拉-拉格朗日法对径向非均匀进气喷湿条件下压气机气液两相流场进行数值模拟，对比研究了叶顶、叶中和叶根局部喷湿三种不同径向位置喷湿条件对压气机气动性能及失稳边界的影响规律，并通过喷湿前后流动径向匹配规律及流动结构的变化解释了影响机理。结果表明：叶顶喷湿相比叶中和叶跟喷湿是更好的喷湿方案，叶顶喷湿时压气机压比和效率升高程度更大，且稳定裕度降低程度更低；当液滴粒径小于50μm，喷射速度大于20m/s时，离心力对液滴径向迁移的影响可以忽略不计，液滴在经过压气机级流道过程中几乎不发生径向迁移，蒸发冷却效应只发生于喷湿的局部叶高范围；由于径向非均匀进气喷湿时压气机内部质量流量会向喷湿的局部叶高范围聚集，导致喷湿的主要影响——即轴向速度的降低和轮缘功的升高在喷湿的局部范围程度较弱，而在没有喷湿的局部叶高范围程度较强。

Abstract:

For the application of wet compression technology， in order to achieve a deeper understanding on the effects of radial non-uniform inlet fogging on aerodynamic performance of transonic compressor， a transonic compressor stage is taken as the research object， and CFD technology combined with Euler-Lagrangian method is adopted to numerically simulate the gas-liquid two-phase flow field of the compressor under the condition of radial non-uniform inlet fogging. The influence of three different radial fogging positions （blade tip， blade middle and blade hub） on the aerodynamic performance and the instability boundary of the compressor are compared. The influence mechanism is explained by the change of flow radial matching and flow structure before and after fogging. The results show that fogging at the top of the blade is a better fogging solution than fogging at the middle and hub of the blade. When fogging at the top of the blade， the pressure ratio and efficiency of the compressor increase more， and the reduction level of the stability margin is lower. When the droplet size is less than 50μm and the injection speed is greater than 20m/s， the effect of centrifugal force on the radial migration of the droplets is negligible， and the radial migration of the droplets almost does not occur in the process of passing through the channel of the compressor stage. The effect of evaporative cooling only occurs in the local span range of the water fogging. In the case of the radially non-uniform fogging， the internal mass flow of the compressor will be concentrated in the local span range of the fogging. As a result， the effect of fogging——the level of axial speed reduction and specific work increase are weaker in the local span range of fogging， but they are stronger in the local span range without fogging.