Analysis of Reverse Circulation Performance of a Large-diameter Reaming Bit with a Guide Column for Mine Rescue Drilling

To address the urgent demand for rapid construction of large-diameter rescue shafts in mine emergencies, this study introduces a reverse-circulation reaming drill bit incorporating a guide column for down-the-hole (DTH) hammer systems. Computational Fluid Dynamics (CFD) simulations were conducted using ANSYS Fluent to analyze the effects of structural parameters—including internal gas-flow channels and guide column geometry—on flow-field characteristics and suction efficiency. Experimental validation using a scaled model confirmed the simulation methodology accuracy, with a maximum deviation of 13.33% between experimental and numerical results. The results demonstrate strong reverse-circulation suction performance, with guide column geometry and flushing-nozzle angle exerting minor influence. Suction capacity shows a negative correlation with flushing-nozzle diameter, a positive correlation with cuttings-channel diameter, and a non-monotonic dependence on suction-nozzle diameter. These findings provide a theoretical and practical foundation for optimizing the design of large-diameter reaming bits with a guide column for high-efficiency emergency drilling applications for mine rescue operations.