工业燃机轴流压气机级间引气结构的压损特性

Pressure Loss Characteristic of an Inter-stage Bleed Air Structure in Axial Compressors of Industrial Gas Turbines

为研究级间引气结构的压损特性,为工业燃机中的相关结构设计提供参考,采用仿真手段对真实的工业燃气轮机多级轴流压气机的级间引气结构进行数值研究,计算域涵盖压气机的多个主流通道和旁路的引气槽道、腔室、管路。结果表明:小引气率下,引气口的气流滞止和折转所导致的压力损失占总损失的五成以上;大引气率下,引气腔室内的流动掺混和引气支管口的流动分离所导致的压力损失占总损失的七成以上。不同区域的流动损失受引气率、引气管路的雷诺数、引气腔室的水力直径影响。下一步可以通过神经网络的方法训练得到零维的级间引气模型,用于进一步的性能评估。

To study the pressure loss characteristics of the inter-stage bleed air structure and provide reference for the design of relevant structures in industrial gas turbines,a numerical study of bleed air structures in real industrial gas turbine multistage axial compressors is carried out by simulation,and the numerical domain including several main flow channels,bleed slot,bleed cavity,and off-take duct of the compressor.The results show that,under a small bleeding rate,the pressure loss due to the flow stagnation and turning at the bleed slot inlet accounts for more than 50%of the total pressure loss.Under a big bleeding rate,the pressure loss due to the flow mixing in the bleed cavity,and the flow separation at the inlet of the off-take duct account for more than 70%of the total pressure loss.The flow loss in different regions is affected by the bleed rate,the Reynolds number of the off-take ducts,and the hydraulic diameter of the bleed cavities.A zero-dimensional inter-stage bleed model can be trained by the neural network method for further performance evaluation.