Study of fluids flow in microchannels

• Main Author: Ng, Yuliang.
• 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/10356/16941
• Institution: Nanyang Technological University

This project involves the study of two fluid flows in PDMS and PMMA microchannels. The objective is to control the laminar fluid diffusion interface (LFDI) by varying parameters such as flow rate ratio, viscosity and under the influence of electric field. Finding the appropriate light source to excite fluorescence flowing in PDMS microchannel is a prerequisite to solve all the problems in this project. A real time automatic controlling interface is crucial to control and indicate the interface location of the laminar fluid. The detection module has an image spot where photocurrent signal is maximum which agrees with the imaging theory. It is found that Rhodamine B as fluorescence dye in PMMA microchannel cannot be excited by green light source. By using ultraviolet as light source, fluorescence (acid yellow 73) flowing in PDMS microchannel can be excited. It has been shown that with a greater flow rate ratio for fluorescence DI water, the channel holdup will be greater and hence more fluorescence will be excited. Blue light source is only able to excite fluorescence (acid yellow 73) flowing in PMMA microchannel. Viscosity, flowrate, electric field’s direction would have significant effect on the delay time of the interface control of fluids in PMMA microchannel. PDMS is relatively inexpensive, optically transparent, and biocompatible which can serve as an alternative to PMMA. PDMS provides a new platform for microchannel fluorescence detection system.