泥沙直径对旋转圆盘装置空化性能的影响研究

Study on the Influence of Sediment Diameter to the Cavitation Characteristics in a Rotating Disk

空化会造成水力机械发生振动,效率下降,而影响空化的因素有很多。为了研究不同泥沙直径对旋转圆盘空化性能的影响,使用SST k-ω湍流模型和Zwart-Gerber-Belamri空化模型对某一卧式旋转圆盘进行全流道三相流动数值模拟。结果表明:旋转圆盘空蚀源附近压力最大值随泥沙直径的增大而减小;当泥沙直径小于0.040 mm时,压力差随泥沙直径的增大而减小,而当泥沙直径大于0.040 mm时,压力差随泥沙直径先快速增大后基本不变;泥沙分布最少的区域为试件所放置的位置,且随着泥沙直径的增大,旋转圆盘空蚀源附近的最大泥沙体积分数和面积均快速增大;当泥沙直径小于0.060 mm时,旋转圆盘的空化受抑制,当泥沙直径大于0.060 mm时,旋转圆盘的空化受促进。

Cavitation will cause vibration and decrease efficiency of hydraulic machinery,and there are many factors affecting cavitation.In order to study the influence of different sediment diameters to the cavitation characteristics of rotating disk,in this paper,SST turbulence model and Zwart-Gerber-Belamri cavitation model were used to simulate the three-phase flow in a horizontal rotating disk.Under the condition of 0.06,the influence of different diameters to the cavitation characteristics in the rotating disk was simulated.The pressure characteristics,sediment distribution and the cavitation volume fraction in the rotating disk were analyzed.The results show that the maximum pressure near the cavitation source is decreased with the increase of sediment diameter;when the diameter is less than 0.04 mm,the pressure difference is decreased with the increase of sediment diameter;when the diameter of sediment is greater than 0.04 mm,the pressure difference is increased rapidly with the increase of sediment diameter first and then basically remains unchanged;the area with the least sediment distribution is the place where the specimen is placed and with the increase of sediment diameter.When the diameter of sediment is less than 0.06 mm,the cavitation of rotating disk is restrained,and when the diameter of sediment is greater than 0.06 mm,the cavitation of rotating disk is promoted.