Structure Design of and Numerical Simulation on an Annular Reverse Circulation Drill Bit

摘要

The reverse circulation drilling technology of hollow through DTH air hammer is a set of efficient coring with DTH air hammer, full-hole reverse circulation with drilling fluids, and continuous coring without power lack. It been successfully applied in mineral resources exploration, water well drilling, infrastructure construction and other fields. We designed a new type of annular reverse circulation drilling bit in order to prevent drilling accident when drilling in complex strata, such as breakage and leakage. In this paper, the computational fluid dynamics (CFD) code, FLUENT, is employed to simulate the flow phenomena of reverse circulation drill bit. Numerical simulation results show that the values of negative pressure of new type annular reverse circulation drill bit which formed in the center channel and the bottom of hole were larger than those of the normal bit. Under the same conditions, the suction quantity from annulus of annular drilling bit is 1.4 times to the normal one.