Abstract
Microbubble formation at a T-shaped microfluidic junction with gas pressure change was experimentally investigated. The gas pressure was actively controlled by using an audio speaker. With this method of bubble generation, we are able to control the size and generation interval of bubble independently. The microchannel has a rectangular cross section of 0.1mm×0.1mm, and channel length of 2.5mm from the junction. As results, we found that rise in gas pressure leads to the elongation of a gas column, the length of which is proportional to both the amplitude and cycle of gas pressure oscillation. The decrease in gas pressure then shortens the gas column. During this shortening period, the necking motion of the column and the following micro bubble generation were successfully achieved at the T-shaped junction.
