| As a research target,the two-phase infiltration behavior of preparation process of diphase continuous composite material is investigated by the improved pseudopotential multi-phase lattice Boltzmann method based on mesoscopic scale.The porous matrix of composite material is constructed by fractal theory.The two-phase infiltration behavior in porous media under different process conditions is simulated by LBM.There are great significance for preparation process of diphase continuous composite material to master the influence law of process parameters in the process of infiltration,to analyse the affect factors of the saturation and to reveal seepage mechanism between ceramic phase and metal phase.In this paper,three kinds of multi-phase pseudopotential models are established respectively,including multi-component multiphase model with viscosity ratio range of 0.01~300,single component multiphase model with density ratio range of 3~1000 and multi-component multiphase model with large density ratio(800).Three models are validated by Laplace’s law,thermodynamic consistency,wetting kinetics and so on.The numerical simulation of the two-phase infiltration behavior in porous media was carried out by three multiphase flow models.The main conclusions are as follows:(1)Firstly,the infiltration problem in fractal porous media is studied by using the large viscosity ratio multi-component multiphase flow pseudo-potential model.It is shown that as the viscosity ratio increases,the viscous fingering phenomenon becomes more apparent for type I norm fractal porous media of porosity ε=0.79 when Re = 24.3,the contact angle θ is 71.11° and 111.3° respectively,and the smaller the infiltration saturation and infiltration time will be;when the viscosity ratio J>90,the viscosity ratio has negligible influence on the infiltration saturation and time.We choose Re=24.3 and J=10,and the infiltration saturation and time will increase with the decrease of the contact angle on type I norm fractal porous media(ε= 0.79)when the wall wettability is hydrophilic;meanwhile the increase of the infiltration saturation and time gradually decreases as the contact angle decreases;the infiltration saturation and time decrease with the increase of the contact angle when the wall wettability is hydrophobic,the saturation and the time gradually increase with the increase of the contact angle.Under the condition of small Reynolds number(Re=16.2~48.6),the smaller the Reynolds number,the effect of wall wettability is more significant and the more obvious the spreading of the infiltrated phase in the longitudinal direction lead to the increase of saturation when J=10 and θ= 71.11°,111.3° respectively on type I norm fractal porous media(ε= 0.79).When Re = 24.3,J=10,100 and θ= 71.11°,111.3° respectively,the decrease of the porous media porosity causes the infiltration phase to firstly take the lead infiltrating the large size pore and to result in non-uniform infiltration so that it will occasion decrease of the infiltration saturation and time.Under the condition of the viscosity ratio J=10 and Re=24.3,the effect of contact angle is the same,and the infiltration saturation and time will decrease with the increasing of contact angle for type I and III fractal porous(ε=0.79).The infiltration and time increase firstly and then decrease with the increase of the contact angle for the type II and IV fractal porous(ε=0.79);and the maximum value occurs in the interval where the contact angle is less than 90°;meanwhile contact angle of the maximum point of the type IV fractal porous is smaller than that of the type II fractal porous.(2)Secondly,the single-component large-density ratio pseudopotential model is used to study the infiltration problem in fractal porous media.And the viscosity ratio J of all simulations is 1 and the type of porous media is norm fractal.It is implied that the effect of porosity on infiltration saturation presents two trends on three different wetting characteristics under the condition of Re=20.25 and Weber number We=0.81.When the wettability of porous wall is hydrophilic or neutral,the smaller the porosity and the higher the saturation;at the same time the infiltration type can be regarded as uniform infiltration;when the wall wettability is hydrophobic,the porosity becomes smaller,the saturation shows a slight downward trend,and the infiltration type is non-uniform infiltration.The infiltration saturation and time increase firstly and then decrease with the increase of contact angle under the condition of ε=0.79,Re=20.25 and We=0.81,and the contact angle of maximum values appears between 64.51° and 77.26°.No matter what the wettability of the porous wall surface is hydrophilic or hydrophobic,and the infiltration saturation increases with the increase of Reynolds number when the viscosity ratio J=1 and ε=0.79;meanwhile the infiltration time decreases with the increase of Reynolds number.With decrease of the surface tension,the Weber number gradually increases from 0.81 to 2.05,and the infiltration saturation and time increase when ε=0.79 and θ=64.51°,126.45° respectively;meanwhile the velocity distribution in the porous media are changed to lead the infiltration phase firstly breaking through the macropores and the small pores infiltration will lag.(3)Finally,the infiltration problem in the channel of the unit porous media is studied by using the large-density multi-component multiphase flow pseudopotential model.The infiltration type and the infiltration mechanism under the condition of large density ratio are emphasized.Re and We of all simulations are 20 and 2.0 respectively.It is shown that under different particle spacing and contact angle,the infiltration type is complete infiltration only in the case of large particle spacing and good wetting characteristics when particle sizes is 50 and DF=0(deviation factor).And the smaller the wall contact angle,the larger the range of particle spacing for complete infiltration will be.The particle spacing ΔL at the boundary of the two infiltration types decreases as the contact angle decreases under the five kinds of particle sizes.The particle size range of the complete infiltration can be increased to some extent by increasing the particle spacing,and the infiltration result is improved.According to the infiltration mechanism,incomplete infiltration can be divided into type 1 and type 2.When the wall wetting property is hydrophilic,the type of incomplete infiltration is type 1,and The particle spacing ΔL at the boundary of the infiltration type decreases as the deviation factor increases.Increase of the deviation factor DF can improve the infiltration process under more conditions,and the infiltration type changes from incomplete infiltration to complete infiltration.When the wall wettability is hydrophobic,the incomplete infiltration type gradually changes from type 1 to type 2 as the particle spacing ΔL and the deviation factor DF increase. |
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