群体平衡方程(population balance equation,PBE)是描述多相流体系中分散相大小与分布随时空变化的通用方程。搅拌反应器内多为多相流体系,考虑到颗粒聚并、破碎等微观机制对颗粒大小、分布、粒数密度等宏观参量的影响,采用PBE对搅拌槽内多相流体系进行数值模拟,可以较准确预测搅拌槽内流场和颗粒的大小与分布。对群体平衡方程在搅拌反应器数值模拟中的应用进行了综述,在简要介绍PBE的基本形式后,讨论了PBE的主要数值求解方法,然后着重介绍近年来采用PBE对搅拌槽内液固沉淀过程、气液及液液体系进行数值模拟的情况,并对今后的研究方向进行了展望。
The population balance equation (PBE) is generally used to describe the particle size distribution of the dispersed phase in multiphase systems. Considering the influence of particle events, such as aggregation and breakage, on particle size and number density, the PBE is a powerful tool for simulation of stirred reactors. The application of the PBE in stirred tanks is reviewed in this paper. After briefing the construction of the general form of the PBE, different numerical methods for solving the PBE are discussed. Specific applications of the PBE in simulation of precipitation processes, gas-liquid and liquid-liquid systems in stirred tanks are also presented.