为改善烟气轮机轮盘的冷却特性,抑制带有催化剂颗粒的烟气入侵盘腔,提出了新型烟气轮机的轮盘和密封结构,基于YL14000C烟气轮机盘腔结构,构建了带有轮盘平衡孔和幅板密封结构的轮盘模型,采用流热耦合数值方法,对比研究了传统及新型盘腔结构的冷却特性、幅板密封特性,探究了盘腔内部冷却蒸汽的分布规律,比较了不同轮盘结构的烟机气动性能。结果表明:轮盘平衡孔使盘腔前侧蒸汽涌入盘腔后侧,与密封蒸汽和少量烟气掺混,提高了轮盘后侧的冷却效果。幅板密封能够阻碍烟气主流的入侵,同时使盘腔两侧的冷却蒸汽分配更加均匀。新型盘腔结构可以增加烟机轴功率10 kW左右。新型盘腔结构能抑制动叶通道结焦、蒸汽影响做功等问题,但其冷却轮盘的能力受到了一定影响。布置轮盘平衡孔后,轮盘前侧的散热量下降,整体冷效有所降低。本文研究结果对盘腔内冷却蒸汽流量分配,抑制烟气入侵以及轮盘结构设计提供了重要参考。

To improve the cooling characteristics of flue gas turbine disk, and restrain the flue gas with catalyst particles from entering rotor-stator disk cavity, a new type of disk and seal structure of flue gas turbines is proposed. Based on rotor-stator disk cavity structure of YL14000C flue gas turbine, a disk model with balance holes and plate seal structures is constructed. Cooling and plate seal characteristics of the traditional and new rotor-stator disk cavity structures are compared by using the fluid-thermal-structural coupling numerical method. The distribution law of cooling steam inside rotor-stator disk cavity is explored, and aerodynamic performance of flue gas turbine with different disk structures is compared. The results show that a certain amount of cooling steam is poured into the back of rotor-stator disk cavity through balance holes, and mixed with sealing steam and a small amount of mainstream flue gas, which improves cooling efficiency of the back of the disk. The plate seal structures can prevent the intrusion of flue gas and make the distribution of cooling steam on both sides of rotor-stator disk cavity more uniform. The new disk cavity structures can increase the shaft power by about 10 kW. Although the new disk cavity structures can inhibit the coking of blade channels and the influence of steam on work, its ability to cool disk is influenced to a certain extent. After the arrangement of balance holes in disks, the heat dissipation from the disk front side decreases, and the overall cooling efficiency is reduced. The results of this paper provide important references for the distribution of cooling steam flow rates in rotor-stator disk cavities, the prevention of flue gas intrusion, and the design of disk structure.