The addition of a polymer to the jet medium enhances its ability to break rock, and the structure of the nozzle plays a vital role in the full utilization of energy. In this paper, a self-propelled porous jet bit with a support plate is designed, which can prevent the drill bit from jamming due to the jet nozzle against the bottom of the well during the drilling process. And the structural design of the cone-converging nozzle is applied to the forward center nozzle. The polymer additive jet flow field and the pure water jet flow field were compared by numerical simulation and experimental investigation. The results show that the polymer additive jet has a longer isokinetic core, and the rock-breaking volume of the polymer additive jet is much larger than that of the pure water jet, and the optimal spray distance is increased. The forward central jet with the conical convergent nozzle structure has more efficient rock-breaking ability.

中文翻译：

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聚合物水溶液在多孔喷嘴中流动的数值模拟与实验研究

在射流介质中加入聚合物增强了其破碎岩石的能力，喷嘴的结构对能量的充分利用起着至关重要的作用。本文设计了一种带有支撑板的自走式多孔射流钻头，它可以防止在钻井过程中由于喷嘴顶住井底而卡住钻头。前中心喷嘴采用锥形收敛喷嘴的结构设计。通过数值模拟和实验研究，对聚合物添加剂射流流场和纯水射流流场进行了比较。结果表明，聚合物添加剂射流具有更长的等速核心，聚合物添加剂射流的破岩体积远大于纯水射流，并增加了最佳喷射距离。