The fundamental understanding of pore scale flow mechanisms associated with the mobilization of trapped oil ganglia during the injection of polymer solutions in porous media requires detailed analysis of viscoelastic flow through pore throats, which can be modeled as constricted capillaries. Despite the vast literature on macroscale and, more recently, microscale viscoelastic flow through contraction–expansion channels, the range of flow parameters covered in previous work does not include the flow dynamics that occur in pore throats of a porous medium, at which the Reynolds number $Re$ is very low and the elasticity number $El$, defined as the ratio of elastic to inertial forces, is very high. We extend previous analyses of viscoelastic flow through constricted planar channels to axisymmetric geometry and flow conditions closer to pore scale flows. The effects of elastic forces are isolated by comparing the flow of a viscoelastic liquid to that of a Newtonian fluid with the similar shear viscosity. The pressure difference is measured as function of imposed flow rate. The different flow regimes are characterized by measuring the instantaneous and average velocity field near the constriction using micro particle image velocimetry ($\mathrm{\mu }-$PIV) technique.

与在多孔介质中注入聚合物溶液过程中与被捕集的油性神经节的动员有关的孔尺度流动机理的基本理解要求对通过孔喉的粘弹性流动进行详细分析，可以将其建模为收缩毛细管。尽管有大量文献报道了宏观尺度和通过收缩-膨胀通道产生的微尺度粘弹性流动，但先前工作中涉及的流动参数范围并不包括在多孔介质的孔喉处发生的流动动力学，在该动力学过程中，雷诺数为$\mathrm{[R}Ë$ 非常低，弹性数 $Ë升$定义为弹性力与惯​​性力之比非常高。我们将通过狭窄平面通道的粘弹性流的先前分析扩展到轴对称几何形状和更接近孔隙尺度流的流动条件。通过比较粘弹性液体与牛顿流体的剪切粘度相似的流体，来隔离弹力的影响。根据施加的流量测量压力差。通过使用微粒图像测速仪测量狭窄部位的瞬时和平均速度场来表征不同的流态（$\mathrm{\mu }-$PIV）技术。