The present invention discloses a central rotary jetting pulse internal-
grinding drilling bit. Different from a conventional PDC drilling bit, the central rotary jetting pulse internal-
grinding drilling bit is added with a pulse generating device, a central rotary jetting
rock breaking device, a negative pressure swabbing device, and a rock cuttings internal-
grinding device. The pulse generating device comprises a
drilling fluid flow channel, a feeding cavity, a
resonant cavity, a resonant tube outlet, and a diverging area, and based on an organ
pipe, generates pulse jets by exciting fluid
resonance. The central rotary jetting
rock breaking device comprises a down-jet bypass flow channel, a down-jet central self-rotating flow channel, a central self-rotating
nozzle, and a blade; and based on mutual coordination between the down-jet bypass flow channel and the self-rotating
nozzle, the
rock breaking and rock clearing efficiency is improved. The negative pressure swabbing device comprises a reverse high-speed flow channel, and a swabbing cavity; negative pressure is formed in the swabbing cavity based on the high-speed characteristic of reverse jets to swab rock cuttings, and the cuttings hold-down effect is reduced. The rock cuttings internal-grinding device comprises a mixing cavity, a
throat, an accelerating cavity, an internal-grinding cavity, an internal-grinding body, a bypass, and a dispersing cavity, and is used for breaking rock cuttings based on a
high pressure acting force and a water-wedge effect; the cuttings carrying efficiency is improved; and a cuttings
bed is cleaned.