相似设计在某风扇改型设计中的应用

针对某涡扇发动机推力增人的动力需求，在充分分析原型风扇性能和流场的基础上，对原型风扇进行了改型设计.改型设计的方法采用“轴流/离心压气机通用叶片造型设计系统”，依据相似理论，在保证第2级风扇进口的相似准则和原型一致，即保证改型与原型第2级风扇在进口的换算流量和换算转速相等的前提下，来增大第1级风扇的流量和压比.经过三维流场计算和分析结果表明：在风扇转速提高到1.011的情况下流量提高到1.071压比提高到1.074，效率提高到1.029，裕度比原型提高了0.8%达到了性能指标的要求改型设计结果比较理想.总体对风扇的性能和整机匹配性分析和评估表明：该风扇改型设计方案能够满足该涡扇发动机推力增大的需求.

Application of similitude theory in modified design of a fan

A modified design of a fan was described,on the basis of enough performance and flow field analysis of original fan,in order to satisfy the more thrust requirement of a turbo-fan engine.The modified design method was: the design tool was "a general blading design system and its application for axial/centrifugal compressor".According to the similitude theory,at the precondition of the equivalence of converse mass flow and converse revolution speed at the second stage inlet,the increase of the mass flow was growing with the pressure ratio.By CFD computation and analysis,all the performances met the requirement and the design result was perfect.The results show that as the speed of the fan increases 1.1 percent,the mass flow increases 7.1 percent,the pressure ratio increases 7.4 percent,the efficiency increases 2.9 percent,and the stall marge increases 0.8 percent.Analysis and valuation of the performance and matching characteristic indicate that this design can satisfy the more thrust requirement of the turbo-fan engine.