摘要
多孔喷嘴是径向水平井技术的核心技术装备,需同时实现高效破岩与强力自进,而目前常用的多孔喷嘴的流量系数一般在0.6左右,其能量转换效率仅为36%左右,严重限制了多孔喷嘴的整体性能。因此,研究多孔喷嘴流量系数影响规律十分必要。根据流量系数定义推导了多孔喷嘴流量系数,试验确定了各孔眼局部阻力系数,并研究了排量、孔眼数量对多孔喷嘴流量系数影响规律。结果表明,多孔喷嘴能量转化效率等于其流量系数的平方;其流量系数由各孔眼流量系数与其权重决定;孔眼流量系数主要取决于其沿程阻力系数与局部阻力系数;绝大部分能量损失由局部阻力损失引起;而孔眼局部阻力系数随着排量增加略有降低,但随着孔眼数目增加而迅速增大。
As the＂core＂of radial jet drilling（ RJD） technology,the multi- orifice nozzle must forcefully self-feed and effectively break the rock to form a radial hole. But nozzle discharge coefficient of the multi-orifice nozzleis always smaller than 0. 6 in most cases that means only less than 36 percent hydraulic energy transfers to the fluid. It is extremely important to study the changing law of the nozzle discharge coefficient of the multi-orifice nozzle. According to the definition of nozzle discharge coefficient,its exact expression of the multi-orifice nozzle was derived. Local resistance coefficient and effects of numbers of orifice and flow rate on the nozzle discharge coefficient werestudied by experiment. Results show that the square of the nozzle discharge coefficient represents the energy conversion efficiency of the multi-orifice nozzle; the nozzle discharge coefficient of multi-orifice nozzle depends on the discharge coefficient and weight ratio of the single orifice; the discharge coefficient of each orifice lies on the frictional resistant coefficient and the local resistance coefficient; most of the energy loss of each orifice wascaused by local resistance; local resistancewould slightly decrease with flow rate while greatly increase with the number of orifice.
出处
《流体机械》
CSCD
北大核心
2017年第1期20-25,54,共7页
Fluid Machinery
基金
国家863计划项目(2015AA043401)
国家科技重大专项(2011ZX05036002)
中国石油大学(北京)科学基金项目(2462013BJRC002)
关键词
径向水平井
多孔喷嘴
喷嘴流量系数
能量转换效率
radial jet drilling
multi-orifice nozzle
nozzle discharge coefficient
energy conversion efficiency
