This paper presents multiscale modeling substantiated with experimental aspects of state, filtration, and motion of the gas-liquid mixtures involving phase transition regions in concentrated volumes applicable to porous media and pipe flows. Based on physics, it is confirmed analytically that actual levels of underpressure in gas-liquids systems are considerably above traditional understanding of saturation pressure at which gas emission from the liquid and its dissolution in the liquid in a form of embryos can occur. It is demonstrated that these processes are not equilibrium processes, and they can also occur on nanoscales and microscales. Thermo-hydrodynamic analyses and experimental investigation of the gas-liquid systems in areas of phase transition presented here have resulted in useful equations governing such flows in filtration in the porous media and in straight pipes.