预估蒸汽轮机叶片颤振的三维方法

发展了一种可考虑叶片间相角变化的三维失速颤振预测方法。二维计算的最小气动阻尼比三维值低，说明取特征截面的二维方法偏于保守，且特征截面的取法具有任意性，故二维方法仅能作为叶片颤振初步预估之用。为提高颤振预估的精度，需用三维计算对二维计算结果进行校核。三维和二维计算均表明叶片间相角对蒸汽轮机叶片气弹稳定性影响很大，叶片颤振预测必须考虑这一关键因素的影响。

A THREE DIMENSIONAL METHOD F OR PREDICTING FLUTTER OF STEAM TURBINE

A three dimensional method,which can con sider non-constant interblade phase angl e,has been developed to predict stall fl utter of last stage steam turbine.The ae roelastic stability of the last stage gr ouped-blades of some steam turbine has b een predicted by the three dimensional a nd the two dimensional methods.Both resu lts indicate that the interblade phase a ngle has important effect on the aeroela stic stability of the steam turbine.The characteristic section of the two dimens ional method is taken at will,and the ca lculation results show that the two dime nsional characteristic section method is conservative.Therefore the two dimensio nal characteristic section method can on ly be tentatively used to predict the ae roelastic stability,the final results mu st be corrected by the three dimensional method.