An experimental study for impact of a drop onto a particle in mid-air: The influence of particle wettability

Drop impact onto a particle in mid-air is a fundamental physical phenomena relevant to many applications involving a fluidized bed, for example, refining of heavy oil or coating of drug particles for pharmaceutical industry. A literature analysis shows that previous studies were focused on collisions of drops with static particles of either spherical or non spherical shapes. This paper reports on experiments conducted at similar impact conditions with water drops and particles made of hydrophobic (polystyrene) and hydrophilic (soda-lime glass) materials. It was observed that at similar Weber numbers, wettability of the particle plays a key role in transition between collision outcomes with formation of a liquid lamella and ligaments. Present investigation is one of the first which reveals quantitative aspects for dynamics of the lamella and liquid ligaments in a particular case of mid-air collisions. (C) 2016 Elsevier Ltd. All rights reserved.