Abstract: To address the health hazards, environmental pollution and explosion risks caused by high-concentration dust diffusion during the initial hole opening of coal mine pneumatic drilling, and to solve the problems of insufficient adaptability and limited dust removal range of traditional orifice sealing spray dust removal devices, a new pneumatic orifice sealing spray dust removal device for drilling with strong adaptability and wide spray dust suppression range was developed. A physical model with a length of 982 mm, a width of 654 mm and a height of 1 000 mm was constructed. A parallel three-stage spray system composed of three equally spaced 65° fan nozzles was adopted, and the included angle between the two inclined surfaces of the main body was set to 60° to optimize the sealing effect. A gas-droplet-dust three-phase flow coupling calculation model was established: the gas phase used the Euler model combined with the Renormalization Group (RNG) k-ε turbulence model; the dust phase was based on the Lagrangian multiphase model combined with the parcel method; the Taylor Analogy Breakup (TAB) model was used for droplet breakup; and the target efficiency was used to characterize the dust capture ability of droplets. An experimental system including the orifice sealing spray dust removal device, dust sampler, high-pressure water pump and other equipment was built. A grid independence test verified that 1.27 million grids met the calculation accuracy requirements. Experimental verification was carried out under 8 different nozzle inlet water pressures (1-8 MPa). The relative errors of dust concentration and dust removal efficiency were 6.98%-8.99% and 3.75%-12.84%, respectively, confirming the accuracy of the model. Through transient simulation, the influences of dust migration distance (0.1-0.6 m), fan nozzle aperture (0.6-2.4 mm), nozzle inlet water pressure (1-8 MPa) and annular air velocity (5-30 m/s) on the dust removal performance for different particle sizes (<10 μm, 10-50 μm, 50<-100 μm) were systematically studied. The results show that the three equally spaced nozzles form a gradient dust removal chain of “front-end inertial interception, middle-end collaborative capture, and back-end diffusion adhesion”. The dust removal efficiency of each particle size increases significantly with the increase of migration distance. The dust removal efficiency of 2.4 mm nozzle aperture for 50-100 μm dust reaches 97.7%; the optimal dust removal efficiency of 1.3 mm nozzle aperture for 10-50 μm dust is 93.4%; and 0.6-1.0 mm nozzle aperture is suitable for capturing dust <10 μm. The dust removal efficiency of <10 μm dust first increases and then stabilizes with the increase of inlet water pressure, reaching a stable state at inlet water pressure of 5-8 MPa. The dust removal efficiency of 10-50 μm dust is optimal at 3-4 MPa nozzle water pressure, while that of 50-100 μm dust is high and stable. When the annular air velocity is 5-10 m/s, the dust removal efficiency of 10-50 μm dust is the best. The dust removal efficiency of <10 μm dust decreases continuously with the increase of velocity, and that of 50-100 μm dust decreases slowly. Through multi-parameter collaborative optimization, the device achieves efficient capture of dust with different particle sizes, providing technical support for dust control in coal mine pneumatic drilling.