Atomization characteristics of a fan air-assisted nozzle used for coal mine dust removal: an experimental study

Abstract

ABSTRACT This article focuses on the atomization characteristics of fan air-assisted nozzles, which is important in the emerging process of dust removal via air-assisted nozzles in underground coal mines. An experimental study on atomization characteristics of a fan air-assisted nozzle was conducted using a custom-built air-assisted spray system. The results reveal that the volume flow rate of the medium, i.e., either water or air, showed a negative exponentially increasing trend as itself pressure increasing and showed a linearly decreasing trend as the other pressure increasing. The drop size distribution met the Rosin-Rammler function. When the air pressure was 0.5 MPa, the drop distribution moved right, and the uniformity coefficient of the distribution fell as the water pressure increased from 0.1 MPa to 0.9 MPa; the drop distribution moved left and the uniformity coefficient raised as the water pressure increased from 0.9 MPa to 1.0 MPa. When water pressure was 0.5 MPa, the drop distribution moved left, and the uniformity coefficient fell as the air pressure increased. The drop size grew downstream; the growth speed was proportional to droplet density and water volume fraction and inversely proportional to drop size. The drop size first tended to increase then showed a decreasing trend as the water pressure increased; the value of the cutoff point increased as the water pressure increased. The drop size decreased as the air pressure increased.