斜螺旋式旋转空化喷嘴性能仿真研究

Simulation Study on the Performance of Oblique Spiral Type Spin Cavitation Nozzle

针对旋转空化喷嘴(Spin Cavitation Nozzle,SCN)开采天然气水合物时能耗高、效率低的问题,设计了一种斜螺旋式旋转空化喷嘴(Oblique Spiral type Spin Cavitation Nozzle,OSSCN)。基于CFD方法,对OSSCN、SCN以及收缩-扩张型喷嘴(Contraction-Dilatation Cavitation Nozzle,CDCN)进行性能对比分析。仿真分析结果表明:与CDCN相比,OSSCN和SCN流场中空化泡的分布更广泛、空化性能更优,且对水合物碎片有着更强的卷吸能力;与SCN相比,OSSCN在水合物壁面处产生的液压冲击能量更大,其径向流速更高,对水合物壁面产生的冲蚀效果更佳;OSSCN的斜螺旋叶轮结构极大地降低了喷嘴液阻、减小了能耗,在与SCN性能相差不大的情况下,OSSCN较SCN降低了约39%的能耗,展现出高效节能的优势。该设计可为空化射流钻水平井+衬管完井技术的商业化应用提供技术支持。

Exploitation of natural gas hydrate using spin cavitation nozzle(SCN)is challenged by the problems such as high energy consumption and low efficiency.To solve these problems,an oblique spiral type spin cavitation nozzle(OSSCN)was designed.Based on the computational fluid dynamics(CFD)method,the performances of OSSCN,SCN and contraction-dilatation cavitation nozzle(CDCN)were analyzed by simulation.The results show that compared with CDCN,OSSCN and SCN have a wider distribution of cavitation bubbles in the flow field,better cavitation performance and stronger entrainment capacity for hydrate fragments.Compared with SCN,OSSCN has a higher radial flow velocity and generates greater hydraulic impact energy at the hydrate wall,resulting in better erosion effect on the hydrate wall.The oblique spiral impeller structure of OSSCN greatly reduces the liquid resistance of the nozzle and the energy consumption.When the performance is not significantly different from SCN,OSSCN reduces energy consumption by about 39%compared to SCN,demonstrating an advantage of high efficiency and energy conservation.This innovative design provides technical support for the commercial application of cavitation jet drilling horizontal well+liner completion technology.