Effects of the fluid flow front instability as it passes through a porous medium under reduced gravity and with chemical interactions between the phases

The paper considers the multiphase seepage of a liquid through a porous medium. We discussed the effects of instability of the liquid interface and proposed a simulation model for the multiple imbibition of the porous medium under variable gravity. The model includes the hysteresis, and various representations of capillary pressure are used during imbibition and drainage. The paper also considers the simulation of instability by transforming the constitutive equations. The method enables to simulate additional blurring of the imbibition front. The simulation results with this method for capillary imbibition of a porous medium under microgravity conditions, as well as for the case when chemical interactions occur between the seeping fluids, are presented.