Abstract
In the present paper, the authors discuss the large scale structure and mechanism of turbulent bubbly flows in a rectangular-vessel-type bubble column (RVTBC).In the experiments, two different size-scale bubbles, mm-scale and sub-mm-scale bubbles, were injected into the water. The mm-scale bubbles were injected into the liquid phase from a sintered metal bubble generator set at the center of the bottom. The sub-mm-scale bubbles were injected uniformly from the bottom of RVTBC. Furthermore, a superficial liquid-phase velocity was added. The 3D profiles of the liquid-phase velocities were measured using a two-component LDA. The profiles of void fraction, diameters, velocities and number density of the mm-scale bubbles were measured using an F-TOP (Four-Tip Optical-fiber Probe). A large scale liquid-phase circulation was formed between the center and the corners by the upward and downward flows.
