水力振动固井工具压力波发生原理研究

Study of Compression Wave Caused by Hydraulic Cementing Tools

振动固井可以提高固井质量,水力振动工具是振动固井的核心装备。分析了现有水力振动工具压力波发生的原理和水击波发生器的原理,结果表明:自振荡喷嘴在外来扰动的作用下,喷嘴内壁边界层的涡结构产生振动,涡结构产生压力脉动,这种自振荡放大的压力振动不具有波的特性,传播的距离有限;节流式压力波发生器通过改变过流面积产生压力波,但过流断面变化有限,压力波振幅小;水击波是一种压力瞬变过程,是一种强间断性质的矩形波,波的能量集中作用在间断面上。利用水击原理设计了双喷嘴水击波发生器,该发生器所产生水击波的振幅可以达到兆帕的数量级,频率由叶轮转速与阀轮叶片个数决定,可以根据需要调节。

Hydraulic vibration tool is the core of vibration cementing equipment which can improve cementing quality. The principle of both compression wave and water hammer wave caused by existing hy- draulic tools were analyzed. The vibration and pulsation of vortex structure in the nozzle wall boundary layer were created in oscillating nozzle under external disturbances. This pressure oscillation with self-amplification does not have characteristics of wave and has limited spreading distance. The pressure wave was generator by changing the flow area of the pressure wave, while the amplitude is limited due to the limitation of the cross section. Water hammer pressure wave is a transient process and is discontinuous rectangular wave. The energy is focused on the cross section. The dual-nozzle water hammer generator was designed using the principles Of water hammer. The amplitude of water hammer wave produced by the generator can be in the magnitude of MPa. The frequency is determined by the rotary speed of impeller and number of vanes which can be adjusted accordingly.