烟气轮机中新型盘腔结构的流热耦合特性

To improve the cooling characteristics of flue gas turbine disk, and prevent cooling steam from entering the main flow path, 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 was proposed. Based on rotor-stator disk cavity structure of YL14000C flue gas turbine, a disk model with balance holes and plate seal structures was constructed. Cooling and plate seal characteristics of the traditional and new rotor-stator disk cavity structures were compared and studied by using the fluid-thermal coupling numerical method. The distribution law of cooling steam inside rotor-stator disk cavity was explored, and the aerodynamic performance of flue gas turbine with different disk structures was compared. The results show that a certain amount of cooling steam is poured from the front to 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 cavity. 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 volume fraction of cooling steam at outlet of new disk cavity increases about 16%, compared with that of traditional disk cavity structure, resulting in an overall disk temperature reduction of 45 K, and the flue gas turbine shaft power improvement by about 10 kW. Although the novel disk cavity structures can adjust the discharge position of cooling steam and inhibit the influence of steam on work, its ability to cool disk is affected to a certain extent.