Oil-water two-phase flow in a horizontal microchannel: Pressure drop and flow pattern

Experimental results of oil water two-phase flow in a horizontal microchannel with hydraulic diameter of 677 mu m are presented. Two series of experiments were performed. The first one was performed with the microchannel initially saturated with a constant oil flow rate. Water injection was then started and increased stepwise. The second series of experiments was performed with the microchannel saturated with a constant water flow rate. Oil injection was then started and increased stepwise. When the steady state was reached for each experiment, the flow rate and the pressure drop were measured and the flow configuration was recorded with a digital camera. Different flow structures were observed. The flow configurations observed for the microchannel initially saturated with oil are droplet of water in oil, slug, slug-annular and annular flow. For the microchannel initially saturated with water, the observed flow structures are droplet of oil in water, semi-stratified and stratified flow. Flow maps were established and compared to the maps of the literature. Experimental results were analysed by using two models: i) the Lockhart-Martinelli model allows a good fit of pressure drop measurements, ii) the homogeneous model allows to predict correctly the results obtained with the microchannel initially saturated with oil.