Abstract: The cavern formation in pseudoplastic fluid exists widely in stirred tank under laminar flow conditions，which is extremely harmful for mass and heat transfer in pseudoplastic fluid，and is an evident for shear- thinning rheological properties. Three mathematical models for predicting the cavern dimensions are spherical model，cylindrical model and toroidal model. Moreover, the progress of the current researches in cavern shape and dimensions development with different impellers is reviewed. These researches have indicated that the cylindrical model（EN model）is better representation of cavern shape and dimensions development in pseudoplastic fluid versus Reynolds number, and the cavern boumdary velocity was determined as 0.01 U_tip at the meantime. The study on the cavern development and flow characteristics in pseudoplastic fluid by computational fluid dynamics（CFD）approach is a certain trend.

Key words: pseudoplastic fluid, cavern, apparent viscosity, rheological index

摘要： 介绍了在假塑性流体层流搅拌中广泛存在的洞穴现象，表明其对物料的传质和传热极为不利；说明了假塑性流体剪切变稀的流变特性，阐述了预测洞穴大小的3种数学模型：球形模型、圆柱形模型和环形模型，同时综述了不同搅拌器洞穴形状及大小变化的最新研究成果，认为圆柱形模型（EN模型）能更好地描述假塑性流体洞穴的形状及其随雷诺数的变化，洞穴边界速度定义为 0.01U_tip；最后指出了利用 CFD 技术研究洞穴变化以及流场特征是必然趋势。

关键词: 假塑性流体, 洞穴, 表观黏度, 流变指数