，有关于粉体孔流
Pressure-driven flow through a porous medium is a useful model system for describing the particles (powders and colloids) circulating under the influence of a pressure gradient. Many applications, such as soil-water retention or transport through a filter medium, rely on this phenomenon.
Particles, such as those made of polyethylene, are typically buoyant and their motion is governed by the competition between the pressure gradient, the gravitational acceleration, and the buoyancy of the particle. The particle’s acceleration and settling velocity depend on the density and size of the particle, the porosity of the medium and the viscosity of the fluid. The velocity distribution of these particles when driven through a porous medium is of great interest as this distribution is the basis for understanding the transport of the particles, which can have effects on the properties of the medium, such as porosity and permeability.
To understand the behavior of a powder medium under pressure, several models have been developed, such as the Bruggeman, Carman-Kozeny and Forchheimer models. These models, based on the classical theory of porous media flow, are used to predict the flow of the powder in the medium and describe the phenomenon of particle separation, which occurs when there is a significant difference in the size and/or density of the particles. Particle separation is typically modelled as a slow process as the particles are driven in different directions by the pressure gradient, resulting in an uneven flow field.
The process of particle separation in porous media is complex and depends on the particle size, porosity of the medium, fluid viscosity and Reynolds number of the flow. To better understand the particle flow, more recent models, such as the Becker-Döring and Turbulent Models, have been developed. These models are based on the understanding that the particle movement is affected by turbulent eddies and thus their flow is more erratic.
Furthermore, many of these models are unable to accurately explain the pressure-driven flow of particles with size and/or density mismatches. To address this issue, recent research has focused on the development of new models that take into account the interactions between the different particles. These models have been used to more accurately predict the motion of the particles in a porous medium.
In conclusion, pressure-driven flow of particles through a porous medium is a complex phenomenon that requires a detailed understanding of the particle size, porosity, viscosity of the fluid and the Reynolds number of the flow. Using the models described above, it is possible to understand the effects of particle separation and predict the movement of the particles. It is hoped that the new models developed will provide further insight into the behavior of particle-based flow and allow for even more accurate predictions.
