变几何多级轴流式压气机特性估算

Characteristic Estimation Method of Variable Geometry Multistage Axial-flow Compressors

由于涉及到变几何工况,燃气轮机系统仿真中压气机低转速工况特性计算最为困难,计算压气机的变几何特性具有重要的意义。利用级叶栅的实验特性,推导出模型级轮周功及效率特性在变几何前后的对应关系。在由压气机总特性辨识出模型级定几何特性的基础上,估算模型级变几何特性,从而可由级堆叠方法计算出压气机在变几何工况下的总特性。新方法考虑到工质密度和转速变化对压气机特性的影响,改进了相似理论并使其可应用于可压缩流体计算中。与试验结果对比表明,新的估算方法可以满足燃气轮机系统仿真的精度要求。

Due to the variable geometry construction of the compressors, the most troublesome part in the development of a component-based gas turbine simulation system is the performance characteristics estimation of the compressors at low rotational speeds. Based on the experimental feature of the cascades, the correspondent relationship of stage shaft power and efficiency between fixed and variable geometry was derived. The variable geometry model stage characteristics were calculated using the identified model stage characteristics. Meanwhile, the overall characteristics of the compressor were calculated stage by stage using the stage stack method. The new technique takes into account the effects of air density change and rotational speeds, thereby improving the analogy theory and making it applicable to compressible flow. Subsequent validation efforts show that the method can satisfy the accuracy requirement in gas turbine system simulation.