INFLUENCE OF THERMODYNAMIC CRITERIA ON THE MOVEMENT REGIME OF A GAS-LIQUID MIXTURE

At a given (usually low) mixture velocity and a specific gas content, a calm separated flow occurs, characterized by a practically non-existent pulsation. As 〖Fr〗_cm increases (either by increasing the velocity or decreasing the diameter), the frequency and amplitude of pulsations increase. The frequency and amplitude of pulsations vary significantly depending on the flow pattern. In addition to the variety of structures, a distinctive feature of the flow of a gas-liquid mixture in a pipe is the high pressure fluctuations caused by the presence of phases with different physical properties, the existence of relative velocity of the components, the high compressibility of the gas-liquid mixture, and other factors. Special forces and thermal interactions occur at the phase interfaces during non-isothermal flow. These interactions have a significant impact on the changes in flow velocity fields, pressures, temperatures, and concentrations as we move from one point in space to another, separated by a phase boundary. In many cases, there are abrupt changes in pressure, temperature, and flow velocity at the phase boundaries. Additionally, even when both phases can be considered incompressible, the gas-liquid system behaves like a compressible fluid. The forms of the combined motion of gas and liquid are extremely diverse and cover all possible states that lie between the motion of two continuous parallel flows that interact only along a single continuous interface, and the motion of a foam flow in which both phases form a complex, thin, and unstable structure. Thus, the forms of motion of two-phase flows are much more diverse and their laws are much more complex than the forms of motion and laws of hydrodynamics of homogeneous media. Therefore, the methods of generalized analysis of experimental data are even more important in this field than in the hydraulics of homogeneous flows. Subject: mass transfer processes in heat flows. Materials and methods: mathematical methods of physical and numerical modeling. Results: as a result of research, dependencies are obtained that allow to reveal the boundary of the transition of modes from annular to cork. Conclusions: the main influence on the processes of transition from the annular mode to the cork mode is the temperature and excess pressure between the vapor and liquid phase in a local point of the system.