汽轮发电机集电环笛形通风结构优化设计

Optimization Design of Flute Ventilation Structure for Collector of Steam Turbine Power Generator

摘要: 汽轮发电机集电环运行过程中，滑环与碳刷之间的摩擦及电流通过等因素造成滑环表面温度升高，由轴端引风机进行抽风冷却。通过分析滑环外侧气流分布与滑环表面对流换热能力的关系，提出在无碳刷区域滑环上方加设多排孔笛形管结构，形成笛形管通风的强化冷却通道｡理论分析与数值计算结果表明：笛形通道对风机流量重新进行分配，冷却空气从孔口内直接冲击到滑环表面发挥了强化换热作用。根据管网模型通过优化设计后得到的最佳笛形管结构，无刷区域滑环表面平均Nu提升了26%，而且同时提高表面换热均匀性。

Abstract: During the operation of collector steam turbinepower generator, the friction between slip ring and carbon brushes and the electric current passing through cause the surface temperature of slip ring to rise, which has to be cooled by the suction fan at the shaft end. Through analyzing the rela-tionship between the airflow distribution and the convective heat transfer coefficients on the sur-face of the slip ring, it is proposed to cover the open area over the slip ring by an arc plank with multi-row holes. Calculations by pipe network and CFD simulations show that the airflow velocity varies along the ring surface. The jet flow impingements through the plank holes enhance the convective heat transfer over the ring surface. Hole diameters are optimized by the pipe network modeling. According to the pipe network model, the average Nu of the slip ring surface in the open area is increased by 26%, and the surface heat transfer uniformity is improved at the same time.