Effect of Air Velocity on Droplet Generation Profile and Spray Dust Removal Efficiency

Abstract

The droplet profile is a critical factor to influence the efficiency of spray dust removal, and is affected by external environment and droplet generation condition. In this paper, the process of droplet generation under airflow was investigated via using the high-speed camera. The droplet generation was divided into two stages according to according to the symmetry of droplet, including Balance and Oscillation. The Balance and Oscillation time both decreased with air velocity increased, which result in the droplet generation time and equivalent diameter shortening in high airflow environment. The droplet left-half width, right-half width and width all increased volatility, Whereas the contact angles decreased volatility and then increased volatility during the Oscillation stage. The oscillating frequency of droplet was found to first decrease and then keep a constant of 15 Hz via analyzing oscillating width and angle. Furthermore, three type-characteristics of droplet centroid location at the detachment were the Windward region, Symmetry axis and Leeward region, and the probability of Leeward region increased as air velocity, whereas probabilities of Windward region and Symmetry axis both decreased as air velocity. These results were mainly that the increase in the difference between dynamic pressure and drag force in the horizontal direction as air velocity to reduce the horizontal component capillary force, resulting in the decrease in the vertical component capillary force which was the main force to resist the droplet generation. These findings offer valuable insights for advancing technology development related to spray nozzle used for wetting dust removal.

Keywords: Droplet generation, droplet width, contact angle, oscillating characteristic, force analyze