风琴管喷嘴空化射流特性数值模拟研究

Numerical Simulation of Cavitation Jet Characteristics of Organ Pipe Nozzle

空化射流在清洗除锈、石油钻探等领域有着广阔的应用前景。风琴管式空化喷嘴因具有良好的空化射流能力而得到了广泛应用。利用Fluent对风琴管喷嘴空化行为展开研究,以入口压力、扩散角、扩散段长度为研究变量,得到了不同工况下喷嘴的气相生成速率、气相体积分布、等速核长度随坐标的变化曲线及流场分布云图。结果表明:气相主要在扩散段近壁面产生,在圆柱段起点和扩散段起点处出现峰值。随着入口压力增大,气相生成速率和等速核长度提高,有气相生成的扩散段长度增加。扩散角的变化对圆柱段空化行为无明显影响,对扩散段气相生成速率、回流区大小及等速核长度影响显著。合理地增加扩散段长度可提高气相生成速率和等速核长度,有利于提高空化射流效果。

Cavitation jet has a wide application prospect in cleaning and derusting, oil drilling and other fields. The organ tube cavitation nozzle has been widely used because of its excellent cavitation jet capacity. In this paper, Fluent was used to study the cavitation behavior of the nozzle of the organ pipe. The inlet pressure, diffusion angle and length of the diffusion section were taken as the research variables to obtain the gas phase generation rate, gas phase volume distribution, constant velocity core length variation curve with coordinates and flow field distribution cloud map of the nozzle under different working conditions. The results showed that the gas phase was mainly generated near the wall of the diffusion section, the peak value appeared at the starting point of the cylinder section and the beginning point of the diffusion section. With the increase of inlet pressure, the gas phase generation rate and the length of the constant velocity nucleus increased, and the length of the diffusion section with gas phase generation increased. The change of the diffusion angle had no obvious effect on the cavitation shape of the cylinder section, but had significant effect on the gas formation rate of the diffusion section, the size of the reflux region and the length of the constant velocity core.Reasonable increase of the length of the diffusion section can increase the gas phase generation rate and the length of the constant velocity core, which is beneficial to improve the effect of cavitation jet.