Coupling effects of porosity and particle size on seepage properties of broken sandstone based on fractional flow equation

Abstract

Therefore, a test system was developed to test the seepage properties of broken rock under different porosities and particle sizes. A nonlinear seepage equation of broken rock was developed based on the Forchheimer equation and the theories of fraction calculus. The influence of the coupling mechanism of the porosity and particle size on the seepage properties of broken rock was analyzed. The results show that the nonlinear seepage equation can describe the nonlinear seepage properties of broken rock well. The relations between the permeability and the porosity and particles size can all be represented through an exponential function. It is thought that watercourses are developed in broken rock with high porosity and large particle size, which shows a stronger hydraulic conductivity capability; however, the inertial potential energy of a non-Darcy flow is relatively small.