(227q) Effect of Surfactant on Secondary Breakup in the Bag Breakup Regime

Effect of surfactant on secondary
breakup in the bag breakup regime

Hui Zhao, Ju-Hui Wu, Jian-Liang Xu, Wei-Feng Li, Hai-Feng Liu*

Key Laboratory of Coal Gasification and
Energy Chemical Engineering of Ministry of Education, East China University of
Science and Technology, Shanghai 200237, People's Republic of China

Shanghai Engineering Research Center of
Coal Gasification, East China University of Science and Technology, Shanghai 200237, People's Republic of China

Abstract:

Secondary breakup is a common phenomenon in a variety
of scientific and engineering applications. The drop encounters an ambient flow
field, and then aerodynamic force causes the drop to deform and break apart
into fragments. This process is referred to as secondary breakup. The drop undergoes
significant deformation and lateral growth during breakup before forming a thin
bag that is characteristic of the bag breakup regime. In this paper drop
breakup which contains surfactant in the bag breakup regime are investigated with
the help of a high-speed digital video camera. The breakup of surfactant-laden
drop is of technological interest and fundamental scientific importance. There
are significant differences in the morphological characteristics
and breakup mechanisms between pure water and water-surfactant mixture. The concentration
of surfactant at the liquid-air interface plays an important role in secondary breakup.
The airflow would induce the advection diffusion of surfactant between interface
and bulk of drop. Temporal properties of drop which contains surfactant are researched
at normal temperature and pressure. Finally influence of surfactant on critical
Weber number is analyzed theoretically.

FIG. 1. Photographs of bag
breakup, air flow direction = right to left (pure water)

FIG. 2. Photographs of bag
breakup, air flow direction = right to left

(water-surfactant mixture)