Abstract: The oxygen mass transfer coefficient is a key parameter in the design of a gas-liquid stirred reactor. It is fundamental for the intensification of an industrial gas-liquid two-phase stirred reactor to study the oxygen mass transfer performance under new types of agitating impellers. Here, a new type of hemi-cambered pitched blade turbine was investigated experimentally to disclose the effects of gas distributor, agitation speed and gas flow rate on the oxygen mass transfer coefficient, the stirring power consumption and the gas holdup. The results showed that the oxygen mass transfer coefficient increased with the increase of stirring speed and gas flow rate; and the empirical equation between oxygen mass transfer coefficient and stirring power consumption and apparent gas velocity was established, which provided a basis for further enlargement of application. Then computational fluid dynamics (CFD) simulations were performed using Eulerian-Eulerian multiphase flow model along with the population balance model to study the hydrodynamics and oxygen mass transfer properties of the hemi-cambered pitched blade turbine with different configuration, agitation speed and gas flow rate. The relative errors between the experimental data and the estimated values were less than 20%, which provided a reliable numerical simulation method for the study of hemi-cambered pitched blade turbine. The configuration of the hemi-cambered pitched blade turbine was optimized to obtain higher oxygen mass transfer coefficients.

Key words: agitating impeller, gas-liquid flow, oxygen transfer coefficient, computational fluid dynamics, population balance model

摘要： 氧传质系数是气液搅拌反应器设计的关键参数，研究新型搅拌桨的氧传质性能对气液两相搅拌反应器的强化有着重要的意义。本文实验研究了气体分布器、搅拌转速、气量对氧传质系数、搅拌功耗及气含率的影响，结果表明，氧传质系数随搅拌转速和气量的增加而增加；并建立了氧传质系数与搅拌功耗和表观气速的经验公式，为进一步放大应用提供了基础。采用欧拉-欧拉多相流模型及群体平衡模型对半弧面新型斜叶桨进行了计算流体力学（CFD）数值模拟研究，模拟研究了不同结构、搅拌转速、气量下的流体力学性能和氧传质系数，模拟计算结果与实验值的相对偏差在20%以内；这为研究这一半弧面新型斜叶桨提供了一种可靠的数值模拟方法；优化了半弧面新型斜叶桨的结构，提高了搅拌釜的氧传质效率。

关键词: 搅拌桨, 气液两相流, 氧传质系数, 计算流体力学, 群体平衡模型