为研究多级无导叶对转涡轮上游叶片尾迹/激波对下游转子气动载荷分布的影响，采用非定常数值模拟方法分析了复杂级间流动对下游叶片表面压力脉动的影响规律。研究表明，多级无导叶对转涡轮取消全部的导向叶片，没有导叶提供预旋的第1级动叶具有吸力面无遮盖段长的特点。吸力面长无遮盖段与相邻叶片尾迹形成类似拉瓦尔喷管的缩扩型尾迹流道，在转转级间非定常干涉作用下，第1级动叶出口马赫数降低，因而在第1级动叶吸力面近尾缘处已有外伸激波的基础上形成了1个新压缩波（尾迹流道激波）。由于尾迹流道激波传播方向与第1级动叶旋转方向相同，在1个周期内尾迹流道激波仅在第2级动叶吸力面进行扫掠。内伸激波反射波从第2级动叶吸力面扫掠至压力面且速度相比尾迹流道激波较快，1个周期内的特定时刻，内伸激波反射波与尾迹流道激波同时作用于第2级动叶吸力面28.8%轴向位置，导致该位置压力脉动峰值显著上升，其峰值达到外伸激波扫掠导致压力脉动峰值的81.2%。外伸激波是引起第2级动叶叶表压力载荷变化的主要因素，其主要扰动区域为第2级动叶前缘，在1个周期内在该区域引起的最大压力脉动峰值达到压力时均值的47.7%。受到多道内伸激波反射波与尾迹流道激波的耗散作用，第1级动叶尾迹强度显著降低，因而其对第2级动叶叶表气动载荷的影响较小。频谱分析结果表明，由于尾迹流道激波与内伸激波反射波的叠加作用效果与外伸激波相近，第2级动叶叶表压力脉动的主频是外伸激波扫掠频率的2倍。

To investigate the impact of wake/shock on the aerodynamic load distribution of downstream turbine blades in a multi-stage vaneless counter-rotating turbine， unsteady numerical simulation was utilized to analyze the influence of complex inter-stage flow on pressure fluctuation on the downstream blade surfaces. The study reveals that in the multi-stage vaneless counter-rotating turbine， all guide vanes are eliminated， resulting in suction side of the first-stage moving blade with an extended uncovered section. The extended uncovered suction side forms a converging-diverging wake flow passage resembling a Laval nozzle in interaction with the wake from adjacent blades. Under the unsteady interaction between the stages， the exit Mach number of the first-stage moving blade decreases， leading to the formation of a new compression wave （wake flow passage shock） near the trailing edge of the suction side of the first-stage moving blade superimposed on the existing suction side trailing edge shock. At specific moments within one cycle， both the reflected shock and the wake flow passage shock act on the 28.8% axial position on the suction side of the second-stage moving blade leading to a significant increase in pressure fluctuation peak value at that location. The peak value reaches 81.2% of the peak value induced by the suction side trailing edge shock sweeping， indicating that the suction side trailing edge shock is the primary factor causing pressure load variations on the blade surface of the second-stage moving blade. The main perturbation region for pressure fluctuation induced by the suction side trailing edge shock wave is the leading edge of the second-stage moving blade， with the maximum peak value of pressure fluctuation in this region within one cycle reaching 47.7% of the mean pressure. Due to the dissipation effects of the reflected shock of pressure side trailing edge shock and wake flow passage shock， the wake strength of the first-stage moving blade significantly decreases， resulting in a minor impact on the aerodynamic load distribution on the blade surface of the second-stage moving blade. Frequency analysis results indicate that due to the combined effects of the wake flow passage shock and the reflected shock of pressure side trailing edge shock， the main frequency of pressure fluctuation on the blade surface of the second-stage moving blade is twice the sweeping frequency of the suction side trailing edge shock.