Effects of droplet formation patterns on the atomization characteristics of a dust removal spray in a coal cutter

To improve the coverage of an external spray in a coal cutter and enhance the coal dust capture efficiency, the atomization characteristics of a dustproof spray were investigated using a self-constructed experimental system by considering different droplet formation patterns. In addition to the droplet diameter, the spray solution consumption, droplet number density and atomization angle were used to more comprehensively analyze the effects of spray pressure and nozzle structure on the atomization characteristics. It was found that the spray field formed by a nozzle with a 1.5 mm outlet diameter and a spray pressure of 5 MPa, had the optimal atomization characteristics, i.e. the droplet diameter was not significantly reduced over 5 MPa, while the solution consumption was optimal (7.69 L/min) at an outlet diameter of 1.5 mm. Droplet diameters were slightly reduced as the solution surface tension decreased. A novel nozzle distribution device, with two nozzles (the optimal distance between them was 15 cm), was designed and installed on the rocker arm of a coal cutter, enhancing the coverage of the dust removal spray. Field application verified that compared to a traditional spray, the total dust and respirable dust control efficiency of the optimized spray field were enhanced by over 8%, effectively improving the working environment in the underground coal mine. [Display omitted] •The atomization features of a spray field under various conditions were investigated.•A novel nozzle distribution device used to enhance the spray coverage was designed.•The optimal droplet formation patterns of a dustproof spray were confirmed.•The optimized external spray can effectively capture coal dust in the working face.