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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.
The unsteady flow analysis program developed by ourselves is used to simulate the unsteady flow in a high-pressure turbine stage under the interaction of wake, potential disturbance and shock wave to study the aerodynamic excitation mechanism of unsteady pressure disturbance on the blade surface. Distortion tracking is used to identify and classify the excitation sources in combination with space-time maps of pressure fluctuations on the blade surface. The relationship between the excitation frequency and the passing frequency of the upstream blades is established by frequency domain analysis of unsteady pressure on the blade surface. The results show that when the axial distance is reduced and the pressure ratio and efficiency of the turbine stage are kept unchanged, the aerodynamic excitation varies with the axial direction The decrease of the distance increases and the high-order component of pressure disturbance may stimulate torsional mode-dominant vibration.