COMPUTATIONAL FLUID DYNAMICS SIMULATION OF WATER-OIL TWO-PHASE SLUG FLOW IN MICROCHANNELS

Oil water slugflow in microchannelsis one of the basic problems of pore-scale seepage. In recent years, more computationalfluid dynamics (CFD) simulations concerning two-phaseflow in microchannels have been developed. However, few simulationshave studied theflow resistance of oil slug in microchannels.In this study, a CFD method was used to simulate the movement of slug in oil water two-phase flow in circular microchannels with diameters of 20 and 200 mu m. The flow resistancesof oil slugs were investigated at different contact angles. The effects of the length and speed of the movement of oil slugs on their flow resistances were analyzed. The simulation results indicate that the shape of the oil slug as well as theflow pattern are influenced by the oil contact angle, defined as the angle between the oil water and oil wall interfaces. A certain number of vortices appear in the front, back, and inside of an oil slug when the oil contact angle is 60 degrees. However,few vortices ariseat the back and front of an oil slug when the oil contact angle is 140 degrees. If the oil contact angle is less than 30 degrees, the microchannel wall is strongly lipophilic and the oil slug beomes an annularfilm.