The Effect of Interfacial Properties and Liquid Flow on the Stability of Powder Islands

• Published in: EPJ Web of Conferences
• Main Authors: Ong Xin Yi, Taylor Spencer E., Ramaioli Marco
• Format: Article in Journal/Newspaper
• Language: English
• Published: EDP Sciences 2017
• Subjects: Physics; QC1-999; Powder Island
• Online Access: https://doi.org/10.1051/epjconf/201714009006; https://doaj.org/article/5c93497cb47d4210909c68e0efa3a480

This study aims at understanding the interplay between the interfacial properties of the powder grains and the characteristics of the liquid flow used to disperse them, in order to obtain an effective dispersion of a powder in a liquid, avoiding air entrainment. The dispersion of grain “rafts” and powder islands “stacks” was investigated both on a static and on a moving air-liquid interface. Powder wicking prevents the formation of a powder island when the grain contact angle is below a critical contact angle. Above the critical contact angle, a powder island forms and grows to a critical depth that depends on grain radius and contact angle. Imposing a flow on the air-liquid interface can either promote water impregnation, reducing the depth of the powder island or destabilise the whole island. In the latter case, the island sinks, forming a heterogeneous powder structure that is wet outside and dry inside.