Three-dimensional steady simulation of a highly-loaded turbine stage with inter-stage cavity has been carried out for analyzing the effects of geometric parameters of radial rim seal cavity on turbine performance. Results show that the influence of radial clearance and axial clearance on aerodynamic efficiency is more distinct than that of axial overhang. Secondary flow loss due to the variation of geometric parameters is the key factor of aerodynamic efficiency change. Axial clearance has the greatest effect on sealing efficiency, radial clearance take second place and axial overhang has the least effect. Larger scale vortex forms due to the acceleration through the hairpin and ex-pansion in the cavity of purge flow is the main reason for the better sealing effect of smaller axial clearance.%为了研究径向封严腔几何参数对涡轮性能的影响,对转/静叶片之间带有封严腔的某高负荷单级涡轮进行了三维定常数值模拟.结果表明,径向间隙和轴向间隙对气动效率的影响程度大于轴向重叠度,几何参数改变导致轮毂二次流损失的变化是影响气动效率的主要因素.轴向间隙对封严效率的影响最大,径向间隙次之,轴向重叠度最小.气流在发卡弯加速后膨胀形成的大尺度旋涡,是轴向间隙能够产生较好封严效果的物理原因.
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