Flow field characteristics and coal dust removal performance of an arc fan nozzle used for water spray.

Abstract

Dust source that presents a ring shape is frequently observed in mining engineering. An arc fan nozzle used for water spray is designed to improve the dust removal efficiency. Based on a study of the spray field characteristics of an arc fan nozzle using volume of fluid (VOF) analysis, it is found that the section of arc fan flow gradually increases, and its mean width of the impact zone is 3.1 times that of the free jet zone. After leaving the guiding object, the central axis velocity of the arc fan flow rapidly increases and then gradually decreases. Based on dimensionless analysis, the calculation formula of the jet speed near the wall is achieved. The relationship between the section geometric features of arc fan flow and the structural parameters of the arc fan nozzle is analysed. A field test completed in the Fucun coal mine indicates that the dust removal efficiency obviously improved with the use of arc fan nozzles. Compared to the full cone nozzles used before, the average removal efficiency for total dust increased by 34%, and the average removal efficiency for respirable dust increased by 32%.