涡扇发动机组合变几何调节优化方法研究

基于单纯形及惩罚函数法，建立了涡扇发动机扩稳和改善性能的多变量变几何组合优化方法。在给定的喷管面积、风扇导叶、压气机导叶及静叶变几何规律下，应用该方法对某型涡扇发动机巡航状态性能和稳定工作范围进行了多变量变几何优化分析。结果表明，在保持推力一定的条件下，实施多变量变几何优化调节不仅可显著提高发动机压缩系统稳定裕度，而且还能明显改善发动机性能。

A New Method of Optimization of Variable Geometry for Enlarging Surge Margin of a Turbofan Engine

Axial flow fans and compressors, in spite of high peak efficiencies obtainable in modern designs, are limited in their applications because of their narrow operating stability range. To get enough surge margin, variable geometry engines have been widely used. It is very important that variable geometry setting rules in modern turbofan engines should be established. Based on sequential unconstrained minimization, a model for obtaining these rules is developed and a new method is given for implementing the model. This model involves the optimization of combined variable geometry controls of guide vane of fan, guide vane and stators of high pressure compressor, area ratio of mixer, and areas of nozzle to obtain minimum specific fuel consumption and enough surge margin. The computer program is also developed. The effectiveness of the proposed model and method is demonstrated by application to a turbofan engine. Under the condition of fixed engine thrust, it is found from simulation results that the surge margin of the turbofan engine is greatly improved. It is apparent that the new method of optimization of combined variable geometry controls for enlarging surge margin of turbofan engine is practical and reliable.