絮凝处理后固相浓度对悬浮液粘度的影响研究

经絮凝处理后的固液悬浮体系,其粘度与固相浓度的关系可由笔者提出的四次多项式描述。该多项式是对只适用于低浓度体系的爱因斯坦线性模型的扩展,新的模型可分别体现流体介质、单个颗粒、线状絮体、面状絮体及体状絮体对体系粘度的贡献。经实验验证,所提出的四次多项式模型可很好地拟合实验数据。在固相浓度较低的时候,絮凝剂用量的增加并不改变体系的流变特性,只在固相浓度达到一定阈值后,絮凝作用才开始明显体现。在絮凝作用达到最大之前,随絮凝剂用量的增加,体系中单个颗粒对悬浮液粘度的贡献逐渐减小,而线状、面状及体状絮体的影响逐渐增大。絮凝剂过量时,絮凝作用下降,体现在体系粘度的降低。

Studying the Effect of Solid Concentration on the Viscosity of Flocculated Suspensions

For the flocculated suspensions,the relationship between viscosity and solid concentration can be described by a fourth-degree polynomial of solid-liquid system.The model,presented by authors,expanded the Einstein＇s liner model that is only suitable for the solid-liquid system with low concentration.The polynomial consists of five items which represent the contributions of fluid medium,dispersed particles,linear flocs,planar flocs and volumetric flocs respectively.The forth-degree polynomial model was verified by experiment.It was shown that the increase of flocculate dosage didn＇t change the viscosity when the solid concentration is less than a threshold value,but a significant increase of the viscosity was observed when a higher dosage of flocculate was used to the suspensions with solid volume fraction larger than the threshold.It was also found that the contribution of dispersed particles to viscosity went down with the increase of flocculate dosage,on the contrary,the influences of linear,planar and volumetric flocs became more and more important.But if the flocculate was over added,the viscosity of suspensions began to be decreased.