旋转流变仪测定易沉降悬浮液流变性的初步探讨

A Study on the Approach to the Rheo-Parameters of Easy Settling Suspensions by using Coaxial Cylinder Viscometer

使用传统的旋转流变仪测量悬浮液流变参数时,若发生颗粒沉降,则测定结果将严重失真。理论分析与实验结果证明,只要使流体以一定的方式循环通过测量空间,则或者颗粒沉降的影响可以忽略,或者这种影响可以定量估计。若循环方式得当,理论上不应对流变测量产生影响。但实际测定时,由于循环空间的狭小及理想循环方式的难以实现,可用一个修正系数对测定结果加以修正。实验证明该修正系数只受循环方式的影响,而与转子转速及流体性质无关。因此在确定的循环方式下,对易沉降悬浮液流变性的准确测定成为可能。

When a traditional coaxial cylinder viscometer was used to measure the rheological parameters of a suspension in which the solid particles sediment, the measurements would be incorrect. In this paper, beth theoretical analysis and experiments showed that if the measured suspension be circulated with a suitable method through the viscometer, the influence of particle settling could be negligible or evaluated quantitatively. If the circulative fluid passed through the flow space symmetrically at only axial velocity, the circulation had no effect on the rheo-parameters. However, the circulation usually changed the rheological properties because of the narrow flow space in the viscometer and the difficulty of the circulation operation. As a result, a efficiency was presented to correct the measurements. It was proved that the efficiency was determined by only the circulation model and irrelevant with the measured fluid and the shear rate. Then the determination of the rheo-parameters of easy settle suspensions with coaxial cylinder viscometer became possible.