基于平均微元级特性的压气机特性线外推方法

在燃气轮机组仿真研究中,确保压气机特性计算的准确可靠是建立燃气轮机组仿真模型的重要前提.针对现有轴流式压气机特性外推方法的不足,对压气机作出合理假设,提出了压气机平均级叶栅特性的概念,进而将压气机分解为若干串联的微元级,分段计算压气机的特性,从而使非设计工况下级进出口相似条件能够得到保证.以雷诺相似定律为基础,将每一个微元级特性外推,得到各微元级特性图,进而重构出压气机整机特性图.结果表明,新方法可以明显减小现有外推方法产生的误差,并由于平均级叶栅特性和虚拟微元级概念的引入,拓宽了压气机特性线获取的途径,提高了外推特性的可靠性.

Extrapolation of Performance Curves of Compressors Based on Averaged Infinitesimal Stage Characteristics

In simulation research on gas turbines,aprerequisite for building a model of a gas turbine set reliably is that the calculated performance of the compressor is realy accurate.In view of the shortcomings of the conventional way of extrapolating performance curves of axial compressors,the concept of average stage cascade performance,together with some rational assumptions,are being presented.The compressor is imagined to be build up of a number of infinitesimal stages and the compressor's characteristic calculated section by section,so that similarity conditions at stage's entrance,under off-design modes of operation,are being satisfied.Based on Reynold's law of similarity,the characteristics of each infinitesimal stage is being extrapolated,the performance curve of each infinitesimal stage obtained,and furthermore the performance curve of the whole compressor constructed.Results show that errors,which appear by using the conventional way of extrapolation,can markably be reduced by the new method.Moreover,by introducing the conception of averaged stage characteristic and that of fictitious infinitesimal stags,the way of obtaining a compressor's performance curve is broadended and the reliability of extrapolation reised.