轴流式冷却循环泵非稳态流激特性数值研究

Numerical Study on Pressure Pulsation Characteristics of Axial-flow Cooling Circulating Pump

轴流式冷却循环泵是舰船动力系统中的关键设备之一,泵内非稳态流动诱发的压力脉动是影响泵振动水平的主要水力因素。运用特定设计方法对某比转速为471的循环泵进行了设计并通过实验测量进行了性能验证。基于非定常数值计算,获得了不同工况下循环泵多个截面上压力脉动系数的变化规律。研究表明:叶轮进口压力脉动系数沿径向呈递增趋势,轮缘处流体激励能量最大且主要集中于叶频;叶轮出口压力脉动系数在轮缘和轮毂处取得极大值,主要激励频率为叶频及其高次谐频;导叶出口压力脉动系数沿径向基本一致,主要激励频率为1/5叶频;叶轮出口诱发的叶频压力脉动是决定泵振动水平的主导因素。研究结论为循环泵减振技术的发展提供了一定的理论支撑。

Axial-flow cooling circulating pump is one of the key equipment in ship power system. The pressure pulsation induced by its unsteady flow is the main hydraulic factor affecting the pump vibration level. The circulating pump with a specific speed of 471 was designed according to a special method and the performance verification was carried out through the experimental measurements. Based on unsteady numerical simulation, the variation of pressure pulsation coefficients in three sections of the pump under different operating conditions were analyzed. The results show that the pressure pulsation coefficient at the inlet of impeller increases along the radial direction. The fluid excitation at the shroud is maximum and mainly depending on the blade passing frequency （fBPF）. The pressure pulsation coefficient at the shroud and hub in impeller outlet section also has a maximum value and the main excitation frequency is fBPF and its higher harmonic frequency. The pressure pulsation coefficient in guide vane outlet section is basically the same along the radial direction and the main excitation frequency is rotation frequency （fR）. The greater pressure pulsation coefficient at fBPF is, the higher vibration will be. The research achievements are helpful to provide some reference for furthering the vibration reduction technology.