大攻角状态压气机分离流及叶片动力响应特性

为研究大攻角状态压气机转子内部分离区的脱落和传播过程及转子叶片对其动力响应问题,对某跨声速压气机级进行了非定常数值模拟和双向迭代流固耦合数值模拟。研究结果表明,在近失速状态,转子叶片通道内会周期性地发生2次叶背分离区的脱落和传播现象。第1个分离区主要表现出轴向传播特性,其会对下游流场产生影响;第2个分离区主要表现出周向传播特性,其会作用于周向相邻的转子叶片,对转子叶排自身产生激励作用,进而影响叶片表面压力分布,引起叶片较强的动力响应,对叶片结构强度的影响不可忽略。非定常/流固耦合计算手段能够较全面地预测流场中激励源的频率、幅值与位置等,在压气机设计阶段应对此类预测工作予以重视,以期更准确地预测叶片共振及动力响应等问题。

Separation flow and blade dynamic response characteristic of compressor at high attack angle

In order to study the shedding and propagation of compressor rotors at high angle of attack,as well as the dynamic response under this transient process,a model with a stage of transonic compressor was simulated with unsteady numerical method and double direction iteration fluid-structure coupled numerical method.The results show that under near-stall condition,the separation regions at suction side move and shed periodically along axial and circumferential directions.The axial separation may influence the flow field and vibration performance of downstream blade rows,while the circumferential separation can impact the adjacent rotor blade,with an excitation brought on rotor row itself and an influence on the pressure distribution of rotor blades.Furthermore,the circumferential separation may cause violent dynamic response which could threaten the structural strength of rotor blades.Unsteady/FSI simulation technology has the ability to forecast frequencies,amplitudes and locations of the excitation sources in flow field.This kind of work should be emphasized during design procedure to assess the resonance and dynamic response of compressor blades.