GENERATING MECHANISM AND SHRINKING CHARACTERISTIC OF MICRO BUBBLES

The generating mechanism of the micro-bubble by the high-speed camera photography was investigated. And shrinking process from micro bubble to micro-nano bubble was investigated by a flow visualization system using micro-scope photography. Micro bubbles were generated by the formation of rotating two phases fluid in the device. The rotating velocity at the exit of the generating device was about 400 revolutions per second.Almost all micro bubbules shrink and change to micro-nano bubbles. Micro-nano bubble is separated from micro bubble on the shrinking rate in time. And it was clear that the critical diameter of micro bubble to start the shrinkage was about 65 μm.