An investigation of droplet flow in micro-channels

• Main Author: Tay, Yoke Gee.
• Other Authors: Wong Teck Neng
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Mechanical engineering::Fluid mechanics
• Online Access: http://hdl.handle.net/10356/40910
• Institution: Nanyang Technological University

The aim of this research report is to study and understand the characteristic of the droplet generated downstream of a formation junction. In microfluidics, there are many approaches toform droplet. Two such methods is the usage of a T-junction of a Y-junction. For this research, the droplet length, droplet distance and droplet generation time for both type of junction are investigated. To extend on the research, addition experiment was done with an expansion bracket. This expansion bracket is added slightly downstream of a T-junction. By varying different flow ratio and flow rates, different set of results can be obtained. Investigation was also done on the effects of flow ratio on the droplet length and distance. Attempt has been made to study the droplet formation in the T-junction using continuity and conservations mass balance equation. Based on the principle of mass balance, explicit expressions for droplet length and droplet distance with respect to flow rates and total length are derived. Combining with the empirical expression obtained from curve fitting, the length of the droplet for a given set of flow rates can be determined. The studies for this research report are done by conducting experiments in micro-channels made in Polydimethylsiloxane with a width and height of 200μm by 100μm. These microchannels are made by using soft lithography followed by oxygen plasma bonding. The solutions used for the experiments are mineral oil with w% w/w Span 80 surfactant (Carrier phase), 0.05% Acid Yellow fluorescence dye solution (Disperse) and de-ionized water (Reagent). An Inverted Fluorescence Microscope together with a camera recorder is used to captures images for analysis.