关键词: 两相流, 分散, 液滴, 碰撞, 聚结

Abstract: One of the most common oil-water flow patterns in a pipeline is dispersion flow formed by one phase dispersed into another in the form of droplets. The flow characteristics of oil-water dispersion are affected by the sizes and distribution of the droplets，thus the study on droplet formation is the basis in oil-water dispersion flow research. This paper studied oil-water dispersion flows formed by two different mineral oils and tap water in a 25.4mm nominal bore stainless pipeline. The droplet pictures were obtained using a high speed video recording technique in an isokinetic sampling system. The results showed that the breaking up and coalescence of droplets occurred at the same time until a dynamic balance was obtained with the dispersed flow parameters achieving a stable state. The time and characteristics of droplets breaking up，coalescence and forming a stable state were obtained，as well as the influence of pump on the time of stable flow formation. The results showed that pump had a strong influence on the characteristics of oil-water dispersion flows.

Key words: two-phase flow, dispersion, droplets, collision, coalescence