旋转磨料射流喷嘴叶轮参数优化设计

Optimization design on swirlers of swirling abrasive water jet nozzle

为增强旋转磨料射流在硬岩地层高效破岩效果,喷射破岩形成较大孔径径向水平井井眼,对喷嘴叶轮参数展开了优化设计。对径向水平井井下工况旋转磨料射流流场进行模拟,研究了叶轮扭转角、长度、直径、叶片厚度和叶片数量等参数对流场速度的影响。结果表明:叶轮扭转角度为影响流场旋流强度的主要因素;减小叶轮直径或增加叶片厚度会缩小流道的过流面积,增加射流的旋转强度,直径影响最大切向速度相差15.1%,厚度影响相差44.6%;叶片数量较多会降低射流冲击速度。在本文条件下,给出了建议性优化喷嘴叶轮结构参数:叶轮扭转角度为630°,长度为30 mm,直径为18 mm,叶片厚度为4 mm,叶片数量为3。所得结果可为径向井旋转磨料射流喷嘴优化设计提供依据。

To enhance rock breaking effects of abrasive swirl waterjet and drill large diameter radial jet drilling(RJD)laterals,swirler geometry parameters of nozzle are designed optimally.Abrasive swirling velocity of jet flow field under the downhole conditions in RJD wells is studied by numerical simulation methods.The effects on flow field velocity of swirling angle,length,diameter,blade thickness and blade number on flow field velocity are studied.The result indicates that the increase of swirling angle is the main reason for the increase of swirl intensity in the flow field.The decrease of the swirler diameter and the blade thickness results in reducing the flow area of the passage and increase the jet swirling intensity.The maximum tangential velocity is affected by the diameter by 15.1%and the thickness by 44.6%respectively.More blades reduce the jet impinging velocity.Under these conditions,the recommended optimal structural parameters of the nozzle swirler are as follows:the swirling angle of the swirler is 630°,the length is 30 mm,the diameter is 18 mm,the blade thickness is 4 mm,and the number of blades is 3.The results provide references for abrasive nozzles design of RJD wells.