A Comprehensive Review of Factors Affecting Dynamic Capillary Effect in Two-Phase Flow

The dynamic capillary effect, which is a common phenomenon of two-phase flow in porous media, has crucial importance in various fields. Several factors, such as permeability, grain size, temperature, fluid properties, and saturation conditions, have a significant impact on the observed dynamic capillary effect. This review systematically analyzes the influence of three categories of factors on the dynamic capillary effect, including properties of porous media and fluids, as well as certain external factors. The main conclusions of available researches are presented and analyzed for each influencing factor. The possible reasons for controversial results are discussed as well. This review shows that the pore throat size of porous media has the greatest impact on the dynamic capillary effect, which can lead to a variation of up to nearly five orders of magnitude in the value of the dynamic capillary coefficient. Meanwhile, the grain size, fracture aperture, and temperature cause the variation of the dynamic capillary coefficient by one or two orders of magnitude. The effect of other factors on the dynamic capillary effect is relatively weakened. Finally, the future perspectives, concluding remarks, and recommendations are presented.