内孔结构对旋转空化发生器水力特性的影响

空化普遍存在于工业生产、舰船推进、航空航天等领域.使用高速相机对闭式循环试验台的旋转空化发生器内部流动进行试验观测，然后基于RNG k ε湍流模型和Zwart Gerber Belamri空化模型开展了旋转空化发生器流场的数值模拟.结果表明数值模拟结果与试验观测数据吻合较好，验证了本文数值模拟方法的准确性和可靠性.受离心力作用，转子孔内的压力从内径到外径逐渐增大.内孔底部由于轴向旋涡的作用，产生较大旋涡并耗散能量.内孔顶部流体与腔体区主流相互作用，在内孔顶侧产生碰撞并形成较小漩涡.不同内孔结构对旋转空化发生器的空化效果具有重要影响，在相同工况下椭圆形内孔的空化率小于圆锥形和圆柱形，说明型线光滑的内孔结构局部损失小，产生的空化较弱.不同内孔结构下，旋转空化发生器内部压力脉动的主频为转频fi或24fi(对应圆周方向开孔排数)，压力脉动最大幅值出现在进口管侧和出口管侧，主要原因是受动静干涉作用影响.

Influence of Inner Hole Structure on Hydraulic Characteristics of Rotary Cavitation Generator

Cavitation is a common phenomenon in industrial production, ship propulsion, aerospace and other fields. In this paper, a high speed camera is used to observe the flow field in a rotating cavitation generator in a closed cycle test rig, and the numerical simulation is carried out based on the RNG k ε turbulence model and the Zwart Gerber Belamri cavitation model. The results show that the numerical simulation results are in good agreement with the experimental observation data, which verifies the accuracy and reliability of the numerical simulation method. Due to the centrifugal force, the pressure in the hole increases gradually from the rotor inside to outside. At the bottom of the hole, large vortexes appear and energy are dissipated due to the effect of axial vortex. The fluid at the hole top interacts with the main flow, impacts on the hole top side, and finally forms a weak vortex. Different hole geometries have an important influence on the cavitation effect of the rotating cavitation generator. Under the same condition, the cavitation intensity of the elliptical hole is less than that of the conical hole and cylindrical hole, which indicates that the hole geometry with smooth profile has less local loss and induces the weaker cavitation. For different hole geometries, the dominant frequency of pressure pulsation in rotating cavitation generator is the rotation frequency fi or 24fi (corresponding to the number of hole rows in the circumferential direction), and the maximum pressure pulsation occurs at the inlet pipe side and the outlet pipe side, mainly due to the influence of rotor stator interaction.