动静叶栅间隙对钠冷快堆二回路泵压力脉动特性的影响

Effect of Clearance of Rotor-Stator Cascade on Pressure Fluctuation in Secondary Circuit Coolant Pump for Sodium-Cooled Fast Reactor

为了研究动静叶栅间隙对钠冷快堆二回路泵压力脉动特性的影响,以钠冷快堆二回路泵原型样机为研究对象,基于剪切应力传输(SST)k-ω湍流模型,对5种导叶进口直径下的模型泵进行非定常数值计算,其中不同模型对应的动静叶栅相对间隙(s)分别为3.030%、4.545%、6.060%、7.575%和9.090%。获得了不同s的模型泵导叶流道区域的压力脉动特性及作用在转子上的径向力特性,分析结果表明:s为7.575%的模型泵,其扬程(H)和效率(η)均为5种模型中最高;导叶流道内各测点的压力脉动主频均为叶轮叶片通过频率,且各测点的叶频处压力脉动幅值沿导叶进口至出口方向逐渐降低;随着动静叶栅间隙增大,各测点处压力脉动及转子所受径向力脉动的叶频处幅值均逐渐降低,且高频脉动成分发生衰减;同时,转子所受径向力矢量大小和方向的波动性也逐渐减弱。

In order to study the effect of the clearance of rotor-stator cascade on the pressure fluctuation in the secondary circuit coolant pump for sodium-cooled fast reactors, the unsteady numerical simulation method based on SST k-ω turbulence model was applied on five model pumps with different clearance of rotor-stator cascade. The relative clearance of rotor-stator cascade of five model pumps were 3.030%, 4.545%, 6.060%, 7.575% and 9.090%, respectively. The characteristics of pressure fluctuation and radial force on the rotor were obtained by unsteady numerical simulation, and the comparison and analysis were made. The results show that both of the head and efficiency of the pump with a relative clearance of rotor-stator cascade of 7.575% are better than those of any other four model pumps. The main frequency of the pressure fluctuation of each measuring point in the guide vane passage is the impeller blade passing frequency, and the amplitude at the impeller blade passing frequency of the pressure fluctuation of each measuring point gradually decreases along the guide vane inlet to the outlet direction. With the increasing of the clearance of rotor-stator cascade, the amplitude at the impeller blade passing frequency of the pressure fluctuation at each measuring point and the radial force fluctuation of the rotor are gradually reduced, and the high frequency fluctuation component decreases. Meanwhile, the fluctuation of the magnitude and direction of the radial force vector of the rotor is gradually weakened.