Air Bubble Injection Into a Liquid Stream in a Minichannel

Air bubble injection experiments have been performed to obtain a better understanding and detailed data on bubble behavior and liquid velocity profiles to be used for validation of 3-D Interface Tracking Models and CFD models. Two test sections used were vertical rectangular minichannels with a width and gap of 20 mm × 5.1 mm and 20 mm × 1.9 mm, respectively. Subcooled water at near atmospheric pressure flowed upward under laminar and turbulent flow conditions accompanied by air bubbles injected from a small hole on one of the vertical walls. The experiments yielded data on bubble formation and departure, and interactions with laminar or turbulent water flow. Instantaneous and ensemble-average liquid velocity profiles have been obtained using a Particle Image Velocimetry technique and a high speed video camera.