Study of multi-fluid flows in microchannel

• Main Author: Chen, Jonathan Mingyao.
• Other Authors: Wong Teck Neng
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Mechanical engineering::Fluid mechanics
• Online Access: http://hdl.handle.net/10356/17110
• Institution: Nanyang Technological University

In this project, PDMS fabricated microchannels will be used to investigate on the possibility of two important phenomena in microfluidics, namely flow switching and countercurrent flow. In the first experiment, flow switching on a pressure driven three-fluid flow was performed using a microchannel with three inlet and five outlet channels. A middle fluid flow was controlled and guided to the desired outlet channel, by varying the flow rates of the three fluids. Using the same microchannel, the second experiment involved flow switching on a pressure driven three-fluid flow, coupled with electroosmotic effects. In this experiment, an electric field was applied along the fluid by a power supply. By varying the voltage applied as well as the polarities of the connections, the middle fluid was controlled and guided to the desired outlet channel. In the last experiment, countercurrent flow was performed on a two fluid flow in a H-shaped channel. The two fluids were injected into the microchannels from opposite ends and the flow rates were varied to obtain countercurrent flow. For all experiments, a fluorescence imaging system was used to observe the flow regime inside the microchannel and an interline coupled charger device (CCD) camera was used to captured the images of the flow regime. Experimental data from the first two experiments indicated that a fluid flow could be guided to the desired outlet channel by varying the flow rates of the fluid as well as by varying the voltage applied. Partial countercurrent flow was also observed from the experimental data of the last experiment.