宽弦空心风扇叶片流固耦合作用下的疲劳分析

Fatigue Life Analysis of Fluid-structure Coupling Characteristics for Hollow Wide-chord Fan Blade

宽弦空心风扇叶片是航空发动机采用的新技术之一。采用间接耦合和直接耦合两种计算方法,对宽弦空心风扇叶片在空气场作用下的结构响应进行了数值模拟和疲劳寿命预测,对比分析了两种方法对叶片寿命的预测结果。结果表明,与间接耦合相比较,直接耦合计算得到的叶片最大应力高出不足10%,两种方法对叶片寿命的预测结果相差很小。在应力放大因子为2的情况下,对比两种耦合方法,叶片的疲劳寿命使用系数几乎为零;在应力放大因子的为3的情况下,同间接耦合相比较,直接耦合随着使用周期的增加,叶片疲劳寿命使用系数也不断增加。

The hollow wide-chord fan blade is one of the new techniques employed by the aero engine. Twofluid-structure interaction numerical methods including indirect coupling and direct coupling were implemented for the hollow wide-chord fan blade undertaking air flow field, and the fatigue life of the fan blade was analyzed. The fatigue life of the fan blade obtained by the two numerical methods was compared. Computational results show that the maximum stress is increased less than 10% with the direct coupling method compared with the indirect coupling one. The using coefficient of the fatigue life is almost zero under the von raises stress amplificatory level of 2 for hollow wide-chord fan blade using either of the two methods. Compared with the indirect numerical method, the coefficient of the fatigue life continuously increases with the increasing period under the von mises stress amplificatory level of 3.