Abstract
The purpose of the study is to perform the velocity and temperature analysis on fluid flow in the recess microchannel and its biomedical application. There are 30 big recess (100 μm width) and 30 small recess (50 μm width) in a 1.04 cm length PDMS microchannel. The study includes the measurement of velocity and temperature profiles in a recess microchannel with single phase flow (water) and two phase flow (water and oil) using PIV technique and TSP technique. Micro- thermocouples were also implanted in the microchannel device for the biomedical application to monitor the temperature variation in different regions inside the microchannel. Computational fluid dynamic was carried out to simulate the velocity and temperature profiles in the microchannel with single phase flow by commercial numerical software ANSYS Fluent. The numerical data from ANSYS Fluent have been compared with experimental results. The temperature development due to the effect from velocity variation can be observed. The lateral temperature distribution from experiment at the region with recess in the microchannel are more gentle than the one in the simulation, and it is because more fluid flowing into the recess in experiment. This is attributed to the round corner at the recess from the fabrication. The micro-thermocouples have been embed in the microchannel to examine the temperature data acquired by TSP technique and the deviation is around 1.3 ℃. During the temperature measure with two phase flow (water and oil), it was observed that the amount of water inside the recess decreased before heating. Several water bath devices were installed underneath the microchannel to resolve this problem and steady water droplets inside recess have been successfully observed.. The velocity profiles of water droplet inside the big recesses have been measured by Micro-PIV technique and vorticity at oil and water interface is 6×10-5s-1. However, the temperature measurements of two phase flow were not success because water droplets keeps reducing in the recesses after the heating even with water bath installation. Finally, the growth of Staphylococcus capitis under various temperature conditions from 25 ℃ ~ 40 ℃ in microchannel devices containing recesses has been examined with single phase (water) fluid condition. It has been identified that the bacterial growth at the temperature between 35 ℃ ~ 37 ℃ is 4 to 7 times higher than other temperature after 3.5 hours. The results observed in current study agree with the data from the literature that reported the best temperature condition for growth of Staphylococcus capitis of 37 ℃.