Abstract

Microfluidic chip is one of the important tools for modem analytical sciences. It is an important and fast developing component for applications in life science. environment science, medicine and chemistry. While its development is spread over tens of years, the basic research on flow mechanism in microfluidics is far behind its application research. This study applies flow visualization techniques to measure the parameters of flow in microchambers for comparing their performance. Geometrical influence of microchambers on flow behavior is found through experimental and theoretical investigations. In order to quantify the effect of geometry, many microfluidic chips were designed with microchambers of different shapes and experimentally tested for various flow rates. As a result, it was identified that symmetrical and asymmetrical shapes have varying effects on the performance of microfluidic chips. In the experiment, the microfluidic chips based on glass platform were fabricated by CMC. This study discusses the main differences and other key factors among many visual observation techniques. This thesis applies micro-particle image velocimetry (oPIV) technique to measure the flow fields in microchambers using de-ionized water. Low power and optical fiber coupled micro PIV experimental system was developed and implemented in-house. This system utilizes an epi-f1uorescent microscope, seed particles, high speed CCD camera, green pulsed laser and optical fiber components to record the particle-image fields. The implemented platform is able to capture the fluid behavior in microchambers. Oblique illumination method was developed for illuminating the flow in microchambers. The oblique illumination method provides a low-cost platform enabling low power studies. Different packaging and interconnection techniques were developed for leak proof sealing of microfluidic ports. Both numerical and experimental investigations have been carried out for different geometries of microchambers under varying Reynolds numbers. Commercial Finite Element Analysis software COMSOL was used to solve the required differential equations. The comparison of simulation results shows a close agreement with experimental results.