固液两相流粒子冲蚀钻头内流道磨损

Bit internal flow passage erosion by solid-liquid two-phase flow impact of particles

针对固液两相流粒子冲蚀钻头内流道磨损机制,应用固液两相流离散相模型(discrete phase model,DPM),建立钻头内流道冲蚀磨损的物理模型,获得粒子参数对内流道磨损的影响规律,并进行室内实验,验证DPM模型的有效性。研究结果表明:粒子对钻头内流道冲蚀磨损主要分布在内流道收缩面,越靠近钻头中心轴线,磨损率越大;随粒子入口速度的增大,内流道平均磨损率增大;随粒子直径的增大,内流道平均磨损率先减小后增大,最后趋于稳定,当直径为2.0 mm时平均磨损率最小;随粒子体积分数的增大,内流道平均磨损率近似呈直线增加;当粒子入口角度为50°时,内流道平均磨损率最大;压力对于内流道磨损影响较小;进行100 h磨损实验后,钻头内流道的磨损率减小了0.80%。

In order to identity the mechanism of bit internal flow passage erosion by solid-liquid two-phase flow impact of particles, the discrete phase model（DPM） was applied to establish the physical model of bit internal flow passage erosion, and the effects of particle parameters on the bit internal flow passage erosion were obtained. Furthermore, the indoor experiments were carried on to verify the validity of the DPM model. The results show that the bit internal flow passage erosion of particles mainly distributes on the contraction surface of bit internal flow passage, and the closer to the bit center axis, the higher the erosion rate is. The average erosion rate of the internal flow passage increases with the increase of the inlet velocity of particles. As the particle diameter increases, the average erosion rate of the internal flow passage decreases first and starts to increases, and then tends to be stable. The minimum average erosion rate is obtained with a particle diameter of 2.0 mm. Furthermore, the average erosion rate of the internal flow passage increases linearly with an increase of the particle volume fraction. When the inlet angle is 50°, the maximum average erosion rate of the internal flow passage appears. In addition, the average erosion rate of the internal has been less affected by the pressure. The erosion loss of the internal flow passage decreases by 0.80% after 100 h erosion experiment.