摘要
为提升高压水射流破碎开采天然气水合物的效率,优化设计一种旋转空化射流喷嘴。利用计算流体力学方法探究不同叶轮数、叶轮加旋角度、入口速度和出口围压对旋转空化射流特性的影响规律,对比分析旋转空化射流和收缩-扩张型空化射流的流场分布规律、涡旋特性及天然气水合物沉积物的破碎特征。研究结果表明:叶轮加旋角度对旋转空化射流的影响明显比叶轮数的影响大,叶轮数及叶轮加旋角度的优化值分别为3个和360°;在喷嘴结构固定的情况下,提高入口速度能获得空蚀及射流冲蚀能力更强的旋转空化射流,而围压升高则会弱化流场中空化云的初生与发展;旋转空化射流因兼具正向冲击、径向张力及周向剪力和“梭形”空化云特点,较收缩-扩张型空化射流有更优的破岩效果;叶轮旋转效应所产生的中心涡使得旋转空化射流的涡结构更加复杂,流场中更易形成“负压”区以提升射流的空蚀能力。
In order to improve the efficiency of waterjet breaking and extracting natural gas hydrate(NGH),a swirling cavitating jet nozzle was designed.The effects of number and angle of impellers,inlet velocity and outlet confining pressure on the characteristics of swirling cavitating jet were investigated based on computational fluid dynamics(CFD).The flow field and vortex characteristics of swirling cavitating jet and convergent-divergent cavitating jet were compared and analyzed.The results show that the influence of impeller angle on swirling cavitating jet is stronger than that of the number of impellers,and the optimization values of the number and angle of impellers are 3 and 360°,respectively.Under the condition of constant nozzle structure parameters,the swirling cavitating jet with stronger cavitation and jet erosion ability can be obtained by increasing the inlet velocity,while the increase of confining pressure will weaken the initiation and development of cavitation cloud in the flow field.With the characteristics of forward impact,radial tension,circumferential shear and"shuttle"cavitation cloud,the swirling cavitating jet has better rock breaking effect than the convergent-divergent cavitating jet.The cooperation of central vortex developed by impeller swirling effect makes the vortex structure of swirling cavitating jet more abundant,and the"negative pressure"area is easier to form in the flow field to improve the cavitation erosion capacity of the jet.
作者
武晓亚
张逸群
赵帅
李根生
WU Xiaoya;ZHANG Yiqun;ZHAO Shuai;LI Gensheng(College of Petroleum Engineering,China University of Petroleum-Beijing,Beijing 102249,China;College of Safety and Ocean Engineering,China University of Petroleum-Beijing,Beijing 102249 China;State Key Laboratory of Natural Gas Hydrate,China University of Petroleum-Beijing,Beijing 102249,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2023年第4期1500-1517,共18页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(51827804,52174009,U20B6005)。
关键词
旋转空化射流
天然气水合物
射流冲蚀
分离涡模拟
涡旋
数值模拟
swirling cavitating jet
gas hydrate
jet erosion
detached eddy simulation
vortex
numerical simulation
