部分交联聚丙烯酰胺悬浮液的触变性及屈服应力

通过流变学研究了部分交联聚丙烯酰胺PCPAM悬浮液的触变性及屈服应力。对PCPAM悬浮液施加阶跃剪切速率，从剪切应力的响应发现PCPAM悬浮液为触变性流体；采用稳态剪切测试研究了不同交联度、不同质量分数的PCPAM悬浮液的剪切应力与剪切速率关系，计算出触变环面积大小，表明PCPAM悬浮液为触变可控的弱触变性流体，并提出了PCPAM的触变机理。采用Herschel-Bulkley模型拟合测试数据，结果表明PCPAM为具有低屈服应力的剪切变稀流体，低交联度或高质量分数的PCPAM悬浮液屈服应力值高，且质量分数对PCPAM屈服应力值影响显著。此外，建立了PCPAM悬浮液在多孔介质里运移时的渗流模型。

Research on Thixotropy and Yield Stress of Partially Cross-Linked Polyacrylamide Suspension

Partially crosslinked polyacrylamide (PCPAM) is a novel oil displacement agent, which not only has a crosslinked network but also linear branched chains. Thixotropy and yield stress of PCPAM suspension were studied. A sudden reduction in shear rate was applied to PCPAM suspension and from the response of shear stress, PCPAM is proved to be a thixotropic fluid.Then the thixotropies of different crosslinking degree and different concentration of PCPAM suspension were studied by thixotropy-loop.It showed that PCPAM suspension was a controllable weak thixotropic fluid and the thixotropic mechanism of PCPAM was proposed. The yield stress of PCPAM suspension was studied by fitting curve according to Herschel-Bulkley model. It revealed that PCPAM suspension was a shear thinning fluid with low yield stress, and the low crosslinking degree and the high concentration of PCPAM suspension both have a larger yield stress. Moreover, a flow model is proposed for PCPAM suspension flowing through porous media.