Hydraulic nozzles are widely utilized for dust removal, cooling, and waste heat recovery in mining production. Nevertheless, the influence of co-flow disturbance on the atomization characteristics within the downstream region of droplet fields remains inadequately understood. In this study, three typical hydraulic nozzles were selected, and the atomization characteristics of the downstream region under different co-flow disturbance intensities were experimentally investigated. The results reveal that increasing co-flow disturbance velocity does not intensify the reduction in sauter mean diameter (SMD), but markedly reduces the dispersed phase fraction (DPF). Under four co-flow disturbance velocities (1.5, 3.0, 4.5, and 6.0 m/s), the relative reduction rates of mean SMD are 6.77%, 3.27%, 4.42% and 2.60%, while those of mean DPF are 13.86%, 35.85%, 52.88%, and 61.86% (e.g., hollow-cone nozzle), respectively. The variation in SMD is achieved through the redistribution of cumulative volume among CV₁, CV₂, CV₃, and CV₄. As the velocity increases from 0 to 3 m/s, the mean SMD of the three hydraulic nozzles exhibits a decreasing trend, which can be directly attributed to the continuous increase in the total cumulative volume of CV₁ and CV₂, and the continuous decrease in those of CV₃ and CV₄. For the hollow-cone and solid square-cone nozzles, the SMD first decreases and then increases, with the turning point occurring at 3.0 m/s, consistent with the variation trend of cumulative volume fractions. In contrast, for the solid-cone nozzle, the SMD continues to decrease at velocities exceeding 3.0 m/s. This work provides both a fundamental understanding of atomization characteristics in the downstream region of hydraulic nozzles under co-flow disturbance and practical guidance for velocity control in mine spray systems.

Fine dust generated during mining operations has become a key factor restricting the sustainable development of mines. The wet chord grid water film (WCGWF) dust removal technology, based on its unique dust–water interaction mechanism, has shown superior performance in removing coarse dust particles. Nevertheless, its dust removal efficiency for fine dust and the corresponding optimization approaches remain unclear. In this paper, experimental dust with a mean particle size of 10.32 μm was prepared. A WCGWF dust removal experimental platform was established. The effects of nozzle atomization characteristics, dust generation rate, chord grid position, and water supply pressure on the total dust removal efficiency of fine dust were systematically investigated. The results show that the hollow-cone nozzle has lower water consumption and a smaller droplet size than the solid-cone nozzle. The total dust removal efficiency of WCGWF remained stable under different dust generation rates (7.0–19.5 g/min). As the distance between the chord grid plate (CGP) and the nozzle outlet increased from 450 mm to 950 mm, the total dust removal efficiency of WCGWF increased from 66.7% to 73.6%. With the water supply pressure rising from 0.3 MPa to 0.7 MPa, the mean Sauter mean diameter (SMD) of the hollow-cone nozzle in the downstream region decreased from 138.9 μm to 90.5 μm. Meanwhile, the spray dust removal efficiency (from 48.1% to 59.6%) and the second-stage collection efficiency of the CGP (from 32.6% to 38.0%) both increased simultaneously. The findings validate the effectiveness of WCGWF dust removal technology as an efficient and environmentally friendly method for fine dust control.