Study on Three-dimensional Particle Migration Model in Porous Media with Dual Deposition Modes

Based on the classical one-dimensional particle migration model，a three-dimensional particle migration model with a double deposition model was established，which considered both the sieve effect and the adsorption effect. Using Laplace and Fourier transforms the general solution of particle migration in saturated semi-infinite porous media under one-dimensional seepage and three-dimensional dispersion conditions is derived. According to the basic solution of point source injection on a semi-infinite body surface，the analytical expression of circular surface source injection is obtained by the integral method. The correctness of the understanding is verified by the degradation of the solution and the parameter inversion of the breakout curve. The influence mechanism of the hydrodynamic dispersion coefficient，sieve coefficient，particle adsorption coefficient，and particle desorption coefficient on the particle migration process was analyzed under constant concentration injection of the circular surface source. The results show that the hydrodynamic dispersion effect accelerates the migration of particles，making the breakthrough time faster and the peak concentration higher. The larger the sieving coefficient and particle adsorption coefficient，the smaller the particle release coefficient，the more particles deposited on the solid matrix，and the smaller the peak particle concentration in the pore. In the case of constant concentration injection of circular surface source，the concentration of particles in porous media increases with time and decreases with depth，and tends to 0 during particle injection. After particle injection is stopped，the concentration of particles in the porous media decreases with time，and there is a concentration peak in depth. The depth of the concentration peak increases with time. © 2023 Hunan University. All rights reserved.