Abstract: Aiming at the improvement of the seal performance of turbine blade tip，optimization research on the labyrinth seal with circular grooves was carried out. Effects of circular groove number，dimension and distribution on the seal performance and turbine efficiency in different pressure ratio cases were analyzed. A primary grope for the mechanism of circular grooves was carried out. Optimized plan of the groove array was given. Results show that，volume effect of the circular groove changed the leakage flow direction by a small angle which decreased the leakage loss. The restrain ability decreased with the increase of pressure ratio. The optimized plan decreased the leakage coefficient by 7.14% and increased the turbine efficiency by 0.59% at the pressure ratio of 1.2. Along with the increase of the radius of the circular grooves from 1mm to 5mm，compared with the smooth style，leakage coefficient decreased by 5.8% while turbine efficiency increased by 0.35%.

Key words: Turbine； Tip clearance；Seal configuration；Circular groove；Aerodynamic performance；Numerical simulation

摘要： 针对涡轮叶顶密封性能的提高，对带圆形凹槽迷宫密封进行了构型优化研究。分析了不同压比时圆形凹槽数量、尺寸及分布对密封性能以及对涡轮做功效率的影响，初步探索了圆形凹槽降低损失的机理，给出了最佳的凹槽排列方案。结果表明，圆形凹槽的容积效应使泄漏流发生小角度偏转，降低了泄漏损失；压比增大，凹槽的节流能力减弱；所得凹槽最佳排列方案在压比为1.2时，泄漏系数降低了7.14%，效率提高了0.59%；单个凹槽半径由1mm增大到5mm，泄漏系数相对于光滑密封减小5.8%，效率增加0.35%。

关键词: 涡轮；叶顶间隙；密封构型；圆形凹槽；气动性能；数值模拟