波浪形非均匀间隙封严结构影响涡轮性能的数值模拟

利用数值模拟的方法研究了波浪形非均匀间隙封严结构和均匀轴向间隙封严结构下轮缘封严气流对涡轮性能的影响.研究表明:燃气入侵与出流结构受到静盘、动盘及主流切向速度的影响,以低于动盘转速同向旋转,并改变了转子的进气条件,增强了压力面马蹄涡强度,因此对转子出口流场造成很大影响.封严气流与上游导叶尾迹的相互作用引起转子通道内熵增,造成涡轮效率的下降.与均匀轴向间隙封严结构相比,波浪形非均匀间隙封严结构使大的入侵与出流结构破碎为小的结构,对涡轮性能的负面影响减小,涡轮效率提高了0.9%.结果证明了波浪形非均匀间隙封严结构在具有较好的封严效果的同时提高了涡轮性能.

Numerical simulation of effects of contoured slot seal configuration on turbine performance

Effects of rim seal flow through uniform slot seal and contoured slot seal configurations on the turbine performance were investigated numerically. The results show that the gas ingress and egress structures are affected by stator disc, rotor disc and the tangential velocity in mainstream, and the rotating speed is less than that of rotor disc with the same direction. As a result, the flow patterns of rotor are changed, which strengthened the pressure side horseshoe vortex, thereby resulting in large changes of flow field of rotor exit. The interaction of seal flow and upstream vane weak induces the entropy rise in the rotor passages, leading to decrease of the turbine efficiency. Compared with uniform slot seal configuration, the contoured slot seal configuration collapses the big ingress and egress structures into smaller ones, and then has less negative effects on the turbine performance. The turbine efficiency is improved by 0.9%. The results prove that the contoured slot seal configuration has better turbine performance as well as better seal effectiveness.