大型核电汽轮机高压调节阀流场特性的数值研究

采用商用计算流体动力学软件CFX,分析了大型核电汽轮机高压调节阀阀座上的消音槽、阀碟空腔和阀壳分流板结构对阀内流场特性的影响。结果表明,消音槽和空腔对阀内流场特性有较大影响,分流板对阀整体气动性能影响不大。全开工况下,消音槽的存在增加了阀门的总压损失,降低临界流量系数,空腔的存在对总压损失和临界流量系数影响极小,但可改善空穴回流区流场的均匀性;部分负荷下,消音槽会导致相同压比下阀门临界流量系数降低,但对总压损失影响较小,空腔结构改善了空穴区内流场的均匀性,对阀门的稳定性有积极作用。分流板使阀门出口流场更均匀,对阀门的气动性能未产生不利影响。

Numerical Study on Flow Characteristics for High Pressure Control Valve of Large Power Nuclear Steam Turbine

By using the commercial computational flow dynamics software CFX, this paper presents how the flow characteristics inside the high pressure control valve of large capacity nuclear steam turbine are structurally affected by muffle, vale disc chamber and splitter plate in the turbine. The results show that the muffle and the chamber had significant influcence on the flow field of the control valve while splitter plate is of little influence. When the valves are in Fully Open condition, the total pressure loss tended to remarkably increase due to existence of the muffle in valve seat, causing reduction of the critical flow coefficient. The valve disc chamber has less effect on the total pressure loss and critical flow coefficient, but it does ipmrove the flow field uniformity of cavitation region. In partially open condition, the existence of muffle causes reduction of the critical flow coefficient, but has little influence on pressure loss, while the valve disc chamber improves the flow field uniformity of cavitation region, which is in favor of stability of the valve. The splitter plate is helpful for creating a more even flow field at valve outlet, which does not have any negative impact on aerodynamics performance.