Slug flow separation

a traditional process in biochemical and pharmaceutical industries

is a valid method to control two-phase flow patterns and enhance heat transfer. The fundamental to study evolution mechanism of two-phase flow patterns is to understand development rules of local parameters by numeric simulation of drainage on micro-channel walls and modulation process of slug flow. The VOF model coupling with dynamic grid adaption was chosen to precisely track gas liquid interface

to simulate movement of the interface at split

and to acquire hydrostatic and dynamic pressure evolution along axial direction and at wall. Results indicated that piston-like movement of bubbles at split was critical to slug flow separation in micro channels. Because of the presence of Laplacian pressure drop at the interface

pressure drop of slug flow was discontinuous with a periodic wavy variation following the interface piston-like movement. The overall pressure drop of slug flow was influenced by local pressure drop at liquid bridge region. Significant pressure drop near bubble head while minimal pressure drop near bubble tail where liquid flow rate was reduced. Such pressure drop characteristics of slug flow is distinguished from other two phase flows.