Oscillatory motion and merging responses of primary and satellite droplets from Newtonian liquid jets

Control strategy and mechanism for satellite droplet reduction

Satellite droplets accompanying the formation of monodispersed particles have serious negative effects in the fields of medicine and food, especially in pill preparation. Therefore, it is of great significance to study control strategy and mechanism for satellite droplet reduction. This paper proposes a simple and efficient device, Drainage Assisted Dropper (DAD), which adds a stainless-steel needle to the center of General Dropper (GD). Experimental and numerical results show the number and volume of satellite droplets of the dripping formed by DAD are significantly reduced compared to those formed by GD. DAD can reduce the liquid volume of satellite droplets with a reduction rate of 87 %, while reducing the size of the primary droplet and increasing the interval between the adjacent primary droplets. Compared with GD, DAD has a smaller cross-sectional area and a larger wetted area, which results in a smaller downward velocity of the liquid. The drainage assisted needle of DAD changes the dripping flow pattern at the outlet of the dropper near the breaking time, causing the residual liquid to be subjected to a higher additional pressure. Less liquid is replenished to the filament, resulting in the filament with a shorter length and a smaller liquid volume. DAD proposed here has a clear development potential and application value in the fields of pharmaceuticals, food, agriculture, and manufacturing.