Study On Permeability Of Porous Media Model Under The Condition Of Equal Void Ratio

The mesostructure structure of sand is used as a prototype,and through some simplifications and assumptions,a permeation model of porous media is established to model the sand permeation evolution process and permeability.Due to the limitation of research methods,diving infiltration model is only considered.According to the particle size distribution,7 kinds of particles with different structural morphology were established for penetration test.The evolution process of permeation growth is observed by infrared monitoring technology.The correlation between permeability coefficient and structural morphological parameters,the relationship between permeability coefficient and morphology of permeation and the influence of structural morphology on the infiltrated morphology after stable infiltration was analyzed.The regular of the permeation evolution growth stage was studied.The main results are listed as following.(1)The fractal dimension of the particle size distribution of the porous medium increases with the increase of the fine particle content.There is a negative correlation between the permeability coefficient and the fractal dimension of the particle size.(2)The structural morphology parameters of porous media are mainly controlled by the arrangement characteristics of the particles and have a low correlation with the particle size distribution.The permeability coefficient of porous media is mainly affected by the distribution and morphology of pores.The larger pore diameter and the better the pore shape,the larger the permeability coefficient.The more dispersed and ordered the pore distribution in the pore media,the larger the permeability coefficient.(3)The penetration growth process can be divided into two stages according to the evolution characteristics of the infiltration morphology.The first stage is from the initial infiltration to the initial penetration of the fluid through the porous media to the downstream.In the first stage,the fractal dimension of the permeation status decreases with time,and the fractal dimension of the permeation boundary increases with time.The permeation status tends to concentrate,and the permeation boundary tends to be complicated.In the second stage,penetration path is continuing to expand until it is stable.The fractal dimension of the permeation status increases with time,and the fractal dimension of the permeation boundary decreases with time.The penetration range is increasing,and the complexity of the penetration boundary is gradually decreasing.(4)In the early period of penetration growth process,the penetration growth is random and the evolution rate changes greatly.When the penetration range of the fluid grows to the main penetration path in the porous media,and the permeation path is basically stable,the penetration evolution rate remains stable.(5)When the permeation of porous media is stable,the larger the fluid penetration range,the greater the permeability coefficient,and the more dispersed the permeation morphology,the lower the degree of grouping,the more uniform the permeation of the fluid in the porous media,and the greater the permeability coefficient.The more dispersed and ordered the pore distribution in the pore media,the more orderly and the more uniform the infiltration morphology.