旋转射流流动规律研究

在前期证明导向叶轮式喷嘴所产生的旋转射流具有较强的破岩成孔能力的基础上,本文对旋转射流的运动规律进行了实验研究。结果表明:旋转射流的速度及压力分布特性明显不同于普通圆射流,在近喷嘴范围内其速度剖面、压力剖面和轴向速度剖面均呈现"M"形分布的特点,切向速度剖面呈现"N"形分布的特点;随着射流向前喷射,射流的横断面不断向外扩散,其速度和压力剖面变得越来越平缓,衰减较快;旋转射流截面最大轴向速度和切向速度与喷距的负指数成正比关系衰减。表明该旋转射流相对于普通圆射流具有较强的横向扩散能力和较弱的轴向传递能力,为合理设计和利用旋转射流提供了依据。

STUDY ON FLOW PRINCIPLES OF ROTATING JET

Based upon the previous demonstrations of that the rotating jet produced by direction conducing jet nuzzles has a stronger capability on rock breaking and borehole making, the flow principles of rotating jet was studied. The obtained experimental results shown that the velocity and pressure distribution of rotating jet are evidently different from that of the conventional circular jet. In the area closed to the nuzzles, its velocity profile, pressure profile and profile of axial velocity represent a "M" shape distribution, and profile of tangential velocity a " N " shape distribution. As the jet prolongs further, the jet profile becomes wider and its velocity and pressure profile become flatter and they attenuate faster. Its maximum axial and tangential velocity attenuate proportionally with the negative index of its distance from the nuzzles. The experimental results also indicated that rotating jet possesses a stronger distributing capability in the direction perpendicular to its axis and a weaker axial propagating capability. The above fact provides information for rational design and use of rotating jet.