轴向间距对转子叶片气动激励的影响

使用自行开发的非定常流动分析程序对尾迹、势干扰和激波共同作用下的某高压涡轮级非定常流动进行数值模拟,研究引起叶片表面非定常压力扰动的气动激励机制.通过叶片通道内的畸变跟踪,结合叶片表面压力扰动时空图,对激励源进行识别和分类;通过对叶片表面非定常压力的频域分析,建立了激励源与上游叶片通过频率的关系;定义压力扰动均方根作为气动激励强度的量化参数,分析叶排不同轴向间距下气动激励的变化规律.结果表明:减小轴向间距并保持涡轮级的落压比和效率基本不变时,气动激励随着轴向间距的减小而增强;压力扰动的高阶分量可能会激励扭转模态为主的振动. 

Effect of axial spacing on aerodynamic excitation of rotor blade

Mechanism of aerodynamic excitation due to wake,potential and shock wave interaction was studied by numerical simulation of unsteady flows in a high pressure turbine stage.The excitation source was identified by analyzing a space-time map and distortion tracing technique.The excitation source was identified as the upstream blade-passing frequency by analysis of unsteady pressure on the blade surface.The unsteady excitation strength was quantified by normalized unsteady disturbances.Several configurations with different axial spacings were calculated.The results indicate that with small changes in axial spacing while maintaining same time-average aerodynamic characteristics,the aerodynamic excitation increases while reducing axial gap and the aerodynamic excitation may excite the blade vibration in a torsion mode.