砂土的突破压力与渗透率实验

符号表A截面积，m2p压力，PaV体积流量，m3／sd颗粒平均粒径，mpc毛细压力，pa孔隙率dth突破直径，mPth突破压力，Pa黏度，kg/(m.s）k渗透率，m2，半径，表面张力，N／mL长度，m1前言三参数模型曾经再现了某种意义的毛细滞后现象1]，但对于存在边界影响的典型重力脱湿和毛细吸湿过程始终未能模拟2]。重要的原因是边界上的两相流体如何处于平衡并不十分清楚。窄筛分沙水中自然沉积的表层实验表明，气体进入湿饱和多孔介质存在一个压力阈值Pth。低于突破阈值时，气体与湿介质处于随遇平衡，只有达到这个值时，气体才能突破表层阻挠进人…

EXPERIMENTS OF PRESSURE THRESHOLD AND PERMEABILITY OF SAND

The relationship between the pressure threshold and the permeability-porosity of thesame sample has been studied. The experimental results show that the relationship betweenthe flow rate and pressure drop in the capillary porous media is similar to that of the lam-inar flow in ordinary pipes and channels. However, the conventional hydrodynamics anddimensional analysis are not sufficient to unify the permeability-porosity relationship. Thepermeability of the narrow screened particle packed bed is not linear function of the squareof the particle or channel size. There is a pressure threshold pth occurring in a very thinlayer of wet sand when gas is forced into them, which is a capillary pressure behavior of theporous media. The threshold diameter, defining as dth=4a/pth, can unify all the experi-mental results of the permeability-porosity. The threshold diameter is neither particle sizenor channel size in the porous media. It is a non-geometrical quantity in length unit.