受轮缘密封结构影响的1.5级涡轮封严流与主流的相互作用以及轮缘密封间流动干扰

为探究动叶上游不同轮缘密封结构封严出流对1.5级涡轮端区流场及轮缘密封间流动干扰的影响区别，通过Shear Stress Transport （SST）湍流模型对无密封腔室，上游密封结构分别为简单斜向、简单径向，下游密封腔室为简单轴向的1.5级涡轮进行了非定常数值模拟。结果表明：轮缘密封间干扰使带径向密封结构模型的下游轮缘腔室内封严效率偏低，并增强了固有的非定常不稳定特性。上游密封结构变化对动叶和第2级静叶流动的影响差异分别位于35%、65%叶高范围内；径向密封结构增加了上游静叶的堵塞效应、动叶入口气流的欠偏转程度、叶根吸力面负荷与14%叶高以上的轮毂通道涡强度，并在第2级静叶入口处产生更多低频压力波动，使其尾缘脱落涡尺度增大但13%叶高以上的轮毂通道涡强度较弱。与无密封腔室相比，通入封严气体总量为主流流量的0.8%时，带斜向密封结构的1.5级涡轮气动效率降低了0.94%，且带径向密封结构的1.5级涡轮气动损失额外增加了0.17%。

Interaction between 1.5-stage turbine rim seal purge flow and mainstream and flow interference between rim seals affected by rim seal structure

To investigate the difference in the effects of different rim seal structures upstream of the rotor on the flow interference between the 1.5-stage turbine mainstream and the rim seal, we conduct unsteady numerical simulation for a 1.5-stage turbine with the endwall, the simple chute and simple radial sealing structures at the upstream and simple axial sealing cavity at the downstream with the Shear Stress Transport (SST) turbulence model. The results show that the interference between the rim seals reduces the sealing efficiency of the downstream rim cavity with the radial sealing structure model, enhancing the inherent unsteady characteristics. The influence of the seal structure change on the rotor and the second stator is within the range of 35% and 65% span, respectively. The radial sealing structure increases the blocking effect of the upstream stator blades, the under deflection of rotor inlet flow, the suction surface load at the blade root, and the hub passage vortex strength above 14% span. In addition, more low-frequency pressure fluctuations are generated at the entrance of the second stator, the trailing edge shedding vortex scale increases, while the hub passage vortex strength above 13% span is weaker. Compared with the endwall structure, the aerodynamic efficiency of the 1.5-stage turbine with the chute sealing structure decreases by 0.94% when the total amount of the purge flow is 0.8% of the mainstream flow, and the aerodynamic loss of the 1.5-stage turbine with the radial sealing structure increases by an additional 0.17%.