Author(s): Zegao Yin; Qiang Zhao
Linked Author(s):
Keywords: Bubble jet; Stagnant water; Population balance model; Gas volume fraction; Bubble diameter
Abstract: Bubble jet is a usual method for improving the artificial aeration, circulation and mixing in liquids. In this paper, a 3-D mathematical model was established to simulate the air-water bubble jets in a stagnant water tank. The Renormalization Group (RNG) k-ε model was used to express the turbulence characteristics between bubbles and water. The population balance model (PBM) was used to describe the coalescence and breakup action between bubbles. Then, the mathematical model was validated with the experimental data of Lima Neto et al. (2008b), and they agree with each other approximately. Furthermore, the mathematical model previous mentioned was used to compute the gas volume fraction and bubble diameter under different conditions. The results show that gas volume fraction and the bubble diameter decrease with the increasing axis distance from the nozzle center. Given the same volumetric flow rate of air at the nozzle, they don’t vary much with the variation of water flow rate. Given the same volumetric flow rate of water at the nozzle, they increase respectively with the increasing volumetric flow rate of air. Volumetric flow rate of air plays a significant role in gas volume fraction and bubble diameter distribution.
Year: 2013