超超临界汽轮机高压缸旁路冷却系统流动特性的研究

Numerical Investigations on Flow Characteristics of 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内部旁路冷却系统内的流场特性,给出了旁路冷却系统内三维流动细节和温度与压力场的分布规律,并与未考虑内、外缸传热作用的纯流动计算结果进行了比较。结果表明:旁路冷却系统中流动形态主要受系统结构和蒸汽自身流动特性的影响;温度场分布不仅受蒸汽流动形态的影响,还取决于高压缸固体域对流体域的传热作用。研究结论验证了,耦合流动传热数值方法能够更加真实地反映旁路冷却系统内温度场的分布。

Numerical investigations on the flow fields of the internal bypass cooling system in the high pressure cylinder of a 1 000 MW ultra-supercritical steam turbine were performed using the flow calculation coupled with the conjugated heat transfer model. The detailed flow pattern, temperature distributions, and pressure distributions in the bypass cooling system were presented. The numerical results obtained by the flow and heat transfer method were compared with those without considering the heat transfer effect of the inner and outer casings. The results show that the steam flow field in the bypass system is mainly influenced by the system structure and the flow characteristic of the steam. However, the steam temperature field is affected by not only the steam flow characteristic but also the heat transfer effect from the solid domain. These findings confirm that it is more realistic to study the steam temperature field in the bypass system with the conjugation of the flow calculation and the heat transfer simulation.