Abstract: In view of the limitation to a gas-liquid surface aerator with single-impeller configurations that the aerated gas bubbles are concentrated in the upper region of the reactor, five dual-impeller configurations are tested with respect to specific power consumption, gas-liquid volumetric mass transfer and mixing time. It is found that the defects of single-impeller configurations are alleviated and the dual-impeller configuration consisting of upper Rushton impeller for surface aeration and lower upward-pumping axial impeller is the best configuration. Such configurations are in accordance with the principle of flow field coupling and enhancing.

Key words: surface aeration, dual-impeller, gas-liquid mass transfer, power consumption, mixing time

摘要： 针对单层桨表面曝气反应器吸入气体主要集中在反应器上部的缺陷，构建了5种双层桨表面曝气反应器构型. 研究了各种构型的传质系数、搅拌功率和混合时间等流体力学特性，表明双层桨构型能改善单层桨构型的缺陷，表面曝气桨与上推式轴流桨组成的双层桨构型的径流桨综合性能最优，符合流场耦合与叠加的原理.

关键词: 表面曝气, 双层桨, 气液传质系数, 搅拌功率, 混合时间