The Flow Field in Air-Water Vertical Bubbling Jets in a Cylindrical Vessel

Bubble frequency and gas holdup in bubbling jets were measured by means of an electro-resistivity probe. The axial, radial and tangential velocity and fluctuation components of water in the bath were measured with a laser Doppler velocimeter. On the basis of the experimental results, the flow field in an air-water vertical bubbling jet in a cylindrical vessel was divided into 4 regions, i.e., the momentum, transition, buoyancy and surface regions with respect to the axial distance from the nozzle exit. The profiles of gas holdup, axial velocity and root mean square value of axial velocity fluctuation in each region were discussed in detail. Also, the flow rate, momentum, and kinetic energy of rising water were determined, being necessary to refine previous theoretical models predicting the fluid behavior induced by bubbles.