旋转流场下PDC钻头的数值模拟仿真

利用fluent软件对简化的PDC钻头进行了三维旋转流场和非旋转流场的数值仿真。结果表明:钻头底部流道的逆流,是由于井底的特殊形状,致使高速流体与井壁碰撞,在黏性力的作用下造成的;钻头四个喷嘴正对分布时,钻头底部中心的涡旋,是由于喷嘴对称分布,使四股流体经井底相互碰撞,在黏性力的作用下造成的。由于涡旋会降低钻井液的携岩能力并对钻头造成磨损,所以有必要减少涡旋的产生。

CFD Numerical Simulation Analysis of PDC Bits in Rotating Flow Field

In this paper, the fluent software is used to simulate the three-dimensional rotating flow field and the non-rotating flow field of the PDC bit. The analysis results show that the reverse flow in the flow channel at the bottom of the drill bit is mainly due to the special shape of the bottom hole, causing the high-speed fluid to collide with the well wall, which is caused by the viscous force; When the drill bit has four nozzles symmetrically, the vortex at the center of the bottom of the drill bit is mainly because of the nozzles symmetrically distributed, so that the four strings of fluid collide with each other after passing through the bottom of the well and caused the vortex with the help of the viscous force. Since the vortex can lose the energy of the drilling fluid and reduce the rock carrying capacity of the drilling fluid and cause wear of the drill bit, the generation of the vortex ought to be reduced.