Research on the Flow Field of the RC600 Down-the-Hole Hammer Drill Bit under Varied Bottom Shapes

It is of great significance to reveal the influence on the reverse circulation performance and cuttings transport efficiency of Large-diameter pneumatic DTH hammers under different bottom structures to improve their cuttings removal efficiency used in drilling applications. These findings hold significant value for improving rock carrying performance in drilling applications. Using multiphase flow numerical simulations, the effects of three different bottom structures—flat-bottom, concave-bottom, and convex-bottom—on flow field characteristics and cuttings transport efficiency were analyzed. The results indicate that the concave-bottom drill bit demonstrated the best performance in airflow concentration and cuttings suction efficiency, achieving the highest cuttings transport efficiency of 97.67%. Although the convex-bottom drill bit exhibited the highest suction ratio at 51.12%, its cuttings transport efficiency was not significantly better than the other designs. These findings provide theoretical support for the design of bottom shapes in large-diameter DTH hammers and have practical implications for enhancing drilling efficiency.