【摘要】 为了精准有效识别屈服型流体的流变特征，基于其剪切应力-剪切速率响应关系，从几何学角度提出了流型转换的高效判别方法，并应用微分分析对该判别法的合理性进行了论证，得到了屈服型流体流型转换的普适性判别方法.针对常用的Power-law, Herschel-Bulkley及Robertson-Stiff流变模型，应用该判别法对模型中流动指数的物理含义进行分析，结果表明：Herschel-Bulkley与Robertson-Stiff模型中的流动指数不能独立表征流体的剪切变稀与剪切增稠行为，其还取决于流体的临界剪切速率，这与模型函数求导结果一致.高速剪切下膏体的流变曲线分析结果表明，该判别法相比流动指数具有较高的准确性和适用性.更多还原

【Abstract】 In order to differentiate the transition between different flow patterns accurately and effectively, an efficient method is proposed in the light of the geometric analysis of the relationship between shear stress and shear rate of yield stress fluids. A differential analysis further demonstrates the rationality of this geometric method, and a generalized approach consisting of the geometric method together with a set of inequalities was deduced for the identification. The generalized method was used to explain the physical meaning of the flow indexes in three typical rheological models, including the Power-law model, Herschel-Bulkley model, and Robertson-Stiff model. The results show that the flow index in Herschel-Bulkley model and Robertson-Stiff model cannot independently characterize the shear thinning and shear thickening behaviors of yield stress fluids. The characterization is shear rate-dependent in parallel, i.e. the critical transition shear rate from shear thinning to shear thickening. The conclusion based on the generalized method is consistent with that indicated by the definitions of the shear thinning and shear thickening behaviors, i.e. the development of the apparent viscosity calculated from the derivation of each rheological model. The analysis of the rheological curves of various cemented pastes over large shear rates shows that the generalized method exhibits reliable accuracy and applicability than the flow index.更多还原