Analysis of internal flow and outlet velocity characteristics associated with dust suppression nozzles and their impact on spray field

Abstract

In order to understand the relationship between nozzle structure and spray field, the present paper conducts velocity-based parametric study on two types of dust suppression nozzles, focusing on the link among nozzle structure, velocity distribution, and the resulting spray field. The simulation investigation indicates that the increase of flow velocity mainly occurs in the convergence section and the outlet region of a nozzle, with its magnitude dictated by the convergence angle, ratio of inlet to outlet diameter, and the length–diameter ratio of the outlet. Based on the velocity distribution characteristic of axis direction and radial direction near different nozzles’ outlet, one can predict that fluid density is higher in the central axis region and lower in the boundary region in spray field with cylindrical outlet, which can form a “solid cone” shape and stable spray. In the case where the nozzle outlet has “dash” type, one can find that the spray field, which associated with this type of nozzle, is a fan-shaped, with the fluid density fluctuating up and down. The above hypothesis has been corroborated by the spray experiments which have been conducted here. The simulation results concerning the internal flow field in dust suppression nozzles can provide guidance over the nozzle design and the parametric optimization and are of great significance to enhance the atomization quality of spray field.