1000MW级核主泵压水室出口压力脉动

Collector discharge pressure fluctuation of 1 000 MW nuclear reactor coolant pump

为了研究压力脉动在核主泵压水室出口处的变化规律及其影响因素,以国内某1 000 MW核电站主泵为研究对象,应用计算流体动力学软件Fluent进行定常与非定常三维数值模拟,得到压水室内部流场特性及计算点的压力脉动情况,并对其进行时域和频域分析.结果表明:回流是引起压水室与出口交接处压力脉动的原因之一;在不同工况下压水室出口及其前后区域内存在明显的压力脉动,偏离额定工况越大,压力脉动波动幅度越大;压水室出口及其前后区域内,上侧的脉动幅度比下侧小,上侧的平均脉动幅度CA在0.9Q时为11.15%,在1.0Q时为9.62%,在1.2Q时为13.78%,下侧的平均脉动幅度,在0.9Q时为13.62%,在1.0Q时为12.53%,在1.2Q时为15.79%;靠近导叶出口处,泵壳两侧处的脉动幅度要大于靠近出口轴线附近的脉动幅度,远离导叶出口处,泵壳内的脉动幅度从上侧到下侧,逐渐递增;在额定工况时转频是各监测点压力脉动的主要影响因素,在小流量和大流量时转频和叶频是各监测点压力脉动的主要影响因素.

To investigate the collector discharge pressure fluctuation characteristics and the related fac- tors in a 1 000 MW nuclear reactor coolant pump, steady and unsteady 3-dimensional numerical simu- lation was conducted to depict the inner flow inherence and detailed pressure content of a domestic pump model. Both time and frequency domain analysis were further put forward. It is shown that re- verse flow is one of the reasons that cause the pressure fluctuations at the joint of the collector and the discharge. Obvious pressure fluctuations exit at the collector discharge and the adjacent area. In addi- tion, the more the operation condition deviates from the design point, the more severe the pressure fluctuations are. The fluctuation amplitude in the upper passage is higher than that in the lower pas- sage. The mean amplitude are 11.5% , 9.62% and 13.78% respectively in the upper passage, while they are 13.62%, 12.53% and 15.79% respectively in the lower one under the flow rates of 0.9Q, 1.0Q, and 1.2Q. At the adjacent diffuser vanes, the fluctuation amplitude near both sides of the ca- sing wall is larger than that near the mid-span line. In the regions far from the diffuser outlet, the fluc- tuation amplitude is increased gradually from the top side wall of casing to the bottom one. The shaft rotating frequency is the major factor influencing pressure fluctuation at ever monitor point when the pump is working at the design point. However, both the shaft rotating frequency and the blade passing frequency are the main factors when it works at off-design points.