密封口环间隙对核主泵CAP1400瞬态特性的影响

Influence of the Sealing Gap on the Transient Characteristics of the CAP1400 Nuclear Main Pump

核主泵密封口环间隙泄漏流会与过流部件主流流道形成交互作用,进而影响核主泵内部载荷,带来不稳定的瞬态流动,给核主泵的安全可靠性带来致命的威胁。为此本文利用RNG k-ε湍流模型来数值求解CAP1400核主泵三维内部流场,并分析密封口环间隙对内部非定常流动特性的影响,该数值方法得到了试验验证。研究结果表明:密封口环间隙流会很大程度上影响核主泵动叶与导叶之间的压力脉动干涉,还会通过叶轮上盖板腔室反馈到叶轮进口,并且增大相应频域上的压力脉动幅值,其最大增幅可达到74.5左右,同时还会导致叶轮叶片径向载荷发生周期性突变,影响核主泵的安全可靠性。

The interaction between the leakage flow of the nuclear main pump seal gap and the main flow channel of the overflow component can affect the internal load of the nuclear main pump leading to an unstable transient flow.This interaction can bring a fatal threat to the safety and reliability of the nuclear main pump.For this reason,this paper uses the RNG k-εturbulence model to numerically solve the three-dimensional internal flow field of the CAP1400 nuclear main pump,and analyzes the influence of the sealing gap on the internal unsteady flow characteristics.This numerical method has been verified using the experimental results.The results show that the seal gap flow will greatly affect the pressure pulsation interference between the rotor blades and guide vanes of the nuclear main pump.Furthermore the seal gap flow can feed back to the impeller inlet through the upper cover chamber of the impeller resulting in an increase in the pressure pulsation amplitude at a corresponding frequency.The maximum increase in the pressure pulsation amplitude can reach about 74.5%leading to a periodic sudden change in the radial load of the impeller blades,which will affect the safety and reliability of the nuclear main pump.