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)