Dynamic behaviour of gas-liquid flow systems

One of the flow type in the gas-liquid system is a gas-assisted displacement process. In this process a fluid confined in either circular or non-circular geometry is displaced by a less viscous fluid. In this displacement, a gas-bubble moves with leaving some liquid on the walls of geometry. The amount of liquid deposited on the walls of the geometry and its shape depend on the type of liquid, gas pressure and the shape of geometry. In this master thesis, the solutions of CMCNa and HECNa having 2.0, 2.5, 3.0 and 3.5 % in terms of weight-base are used to examine the gas-assisted displacement. The air used as a displacing fluid is injected at pressures of 0.2, 0.5, 0.7, 1.0, 1.5, 2.0, 2.5 and 3.0 psi. The experiments are performed in a tube having inner diameter of 5.3 mm and a length of 55 cm is used at isothermal conditions. Rheologic properties of fluids used in the experiments are determined by using Brookfıeld RVDV-II+ model viscometer and the relationships between Ca and the fraction of liquid deposited on the walls of the geometry are determined at the temperature of 20, 30, 40, 50 and 60 °C. The viscosities of polymer solutions used in the experiments are determined as a function of shear rates and it reveals that fluids are pseudo plastic. It is observed that the fraction of liquid deposited on the walls of the tube decraeses with increasing temperature of the fluid. On the other hand, it is observed that the film thickness on thewalls increases with increasing concentration of polymers solutions. In all the concentrations used in the experiments, it is found that the fraction of CMCNa solutions is larger than that of HECNa solutions. Key words: Two-Phase Flow, Gas- Assisted Displacement, non-Newtonian Fluids.