Numerical simulation and engineering application of multistage atomization dustfall at a fully mechanized excavation face

To explore the effect of atomization and dustfall at a fully mechanized excavation face with a multistage external spray, numerical simulation of an airflow-dust field and airflow-droplet field was carried out using the theory of computational fluid dynamics (CFD). The migration and distribution of dust and droplet particles with airflow were analyzed, and the effect of multistage atomization was explored via numerical simulation and field measurements. The results show that dust mass concentrations up to 2000 mg/m(3) are generated near the head and gradually diffuse over 35 m on the downwind side of the roadheader, and the average droplet concentration exceeds 0.2 kg/m(3). The first, second and third stages of external spray settle a large portion of the high dust concentration. The fourth stage of external spray settles the dust at the point of transfer, and the fifth stage of external spray forms a water curtain at the back of the roadway to minimize dust diffusion. The field measurement shows that the multistage external spray dust suppression system can effectively reduce the dust concentration at the 33(down)03 fully mechanized face, with dust removal rates for total dust and respirable dust of 76.04% and 84.3%, respectively. The dustfall effect is remarkable.