针对汽轮机叶顶密封泄漏流引发的掺混损失与转子稳定性问题，提出导流叶栅调控流场结构提升叶顶密封性能方法。建立叶顶密封及导流叶栅三维计算流体力学模型，开展导流叶栅调控下叶顶密封间隙流场特性研究，分析叶栅安装位置、数量对密封动静特性影响。结果表明：导流叶栅调控可减小泄漏流与主流周向速度差、降低掺混损失，其中入口段布置效果优于出口段。此外，导流叶栅型线设计会产生额外动能耗散、提升泄漏流阻，泄漏量降低可达约4%。动力特性分析表明，入口段布置导流叶栅可增加叶顶密封有效阻尼，提升系统稳定性，且提升效果与叶栅数量成正比；出口段布置，有效阻尼为负值，不利于系统稳定。综合气动与稳定性要求，在叶顶入口每个节距内布置4-5个导流叶栅可实现最优性能。

To address the mixing loss and rotor instability issues induced by leakage flow in turbine tip seals, this study proposes a flow control method using guide vanes to optimize the flow field structure and enhance tip sealing performance. A three-dimensional computational fluid dynamics (CFD) model of the tip seal and guide vanes was established to investigate the characteristics of the tip clearance flow field under guide vane regulation. The effects of vane installation position and quantity on the static and dynamic characteristics of the seal were analyzed. The results demonstrate that guide vane regulation reduces the circumferential velocity difference between the leakage flow and the main flow, thereby decreasing mixing loss, with superior performance achieved when vanes are installed at the inlet section compared to the outlet section. Additionally, the aerodynamic design of the guide vanes introduces additional kinetic energy dissipation, increasing leakage flow resistance and reducing leakage by approximately 4%. Dynamic characteristic analysis reveals that guide vanes installed at the inlet section enhance the effective damping of the tip seal, improving system stability, with the damping effect proportional to the number of vanes. In contrast, outlet section installation yields negative effective damping, adversely affecting stability. Considering both aerodynamic and stability requirements, optimal performance is achieved by arranging 4-5 guide vanes per pitch at the tip inlet.

TK263