液动冲击器缸体结构优化设计

Optimized design of the cylindrical structure of hydrodynamic impactor

为解决液动冲击器在使用过程中缸体出液孔口出现冲蚀坑的问题,采用CFD分析法对缸体工作过程进行模拟仿真,根据流场模拟结果提出结构改进方法,将缸体流道从径向水平改为与水平方向成45°角的结构。研究结果表明,缸体流道沿径向水平时会引起出液孔口附近液体流速和压力突变,产生脱流回流现象,导致缸体出液孔口附近发生严重冲蚀;结构改进后流场分布情况得到明显改善,且能满足缸体强度要求,延长了冲击器缸体的使用寿命。现场试验中改进后的液动冲击器的平均钻速比改进前提高了34%。

To solve the problem that erosion pit will appear in the liquid outlet of the cylinder in the use of the hydrodynamic impactor,a simulation of the impactor's operating process was conducted,adopting numerical simulation method. Improvement of the structure is put forward according to the simulation results of the flow field. That is to say,the radial level of the cylindrical flow channel is changed as a structure with 45 degrees to horizontal level. The results show that,when cylindrical flow channel follows a radial level,a sudden change will arise with the flow rate and pressure of the liquid near the liquid outlet,resulting in stall and reflux as well as serious erosion near the cylindrical liquid outlet. After improvement of the structure,the distribution of the flow field is improved remarkably and the cylindrical requirements can be satisfied. The service life of the impactor cylinder is thus lengthened. In the experiment,the average drilling rate increases by 34%,compared with that before improvement.