自转式空气锤活塞动力学仿真与试验

Dynamic Simulation and Experiment of the Piston ofSelf-rotating Air Hammer

自转式空气锤作为一种新型气体钻井用井下动力工具,通过边冲击边旋转来破碎岩石。自转式空气锤在试验过程中活塞出现了多次断裂现象。文章通过对自转式空气锤活塞实际断裂情况分析,运用动力学仿真分析活塞冲击钎头过程中的受载情况,根据仿真结果再对活塞结构进行优化,以提高活塞强度,优化后的结构在整个撞击行程中,结构受力呈现下降的趋势,尤其在0.6 ms时刻下降最为明显,即改进后的结构比改进前的结构应力降低了43.9%,改善效果明显。在后续的自转式空气锤现场试验中未出现活塞断裂情况,验证了动力学仿真和结构优化效果。

As a new type of downhole power tool for gas drilling,the self-rotating air hammer breaks rocks by simultaneous impact and rotation.The piston of self-rotating air hammer broke several times during test.In this paper,the load of the piston impacting on the bit is analyzed by dynamic simulation,through analysis of the broken piston of self-rotating air hammer.The piston strength is improved by optimizing its structure based on simulation results.The stress of optimized structure is in a downward trend throughout the entire impact stroke with the most significant decrease at 0.6 ms,the stress of improved structure is reduced by 43.9%compared to the previous one.The improvement effect is significant.During the subsequent on-site tests of the self-rotating air hammer,there was no broken piston,which has verified the effectiveness of dynamic simulation and structural optimization.