超超临界汽轮机高压缸旁路冷却系统冷却特性研究

Numerical Investigation on the Cooling Characteristics of the Bypass Cooling System in High Pressure Cylinder of Ultra-Supercritical Steam Turbines

采用耦合流动计算和共轭传热的数值方法研究了1 000MW超超临界汽轮机高压缸旁路冷却系统的冷却特性,给出了系统作用下高压缸内外缸和轴端平衡活塞等固体部件的温度场分布特性,对比了有/无内部旁路冷却系统在不同条件下高压缸的温度场。研究结果表明:超超临界汽轮机高压缸旁路冷却系统能有效冷却高压缸内缸和轴端平衡活塞,使整体温度水平明显下降,高压缸外缸温度略有上升,高压缸内缸在旁路冷却系统的作用下温度分布均匀;对于阶梯式平衡活塞的冷却作用,主要取决于3段汽封长度、汽封齿间隙及平衡活塞前径向间隙。

The cooling performance of the bypass cooling system in the high pressure cylinder of a 1 000 MW ultra-supercritical steam turbine was numerically investigated using conjugation of the flow calculation and heat transfer method. The temperature distributions of the inner case and outer case of the high pressure cylinder, and the thrust equilibrium piston were obtained. The comparison between the temperature distributions of the high pressure cylinder with and without the bypass cooling system was performed under different conditions. The results show that the high pressure inner case and the thrust equilibrium piston can be effectively cooled by the bypass cooling system. The temperature of these solid domain decreases obviously while the outer case temperature increases slightly. In addition, the temperature distribution of the inner case is relatively uniform with the bypass cooling system.