Two-phase gas/liquid flow is important in a variety of chemical engineering applications, such as the simultaneous transport of gas and oil in horizontal pipelines or in vertical wells, condensate return lines flashing into steam, vapor-liquid feed lines entering distillation columns and refrigerant-return lines, that must maintain a specific vapor-liquid ratio for efficient operation. The major complexity in two-phase flows results from the growth and collapse of the gas-liquid interfaces that can give rise to various flow regimes. The linear velocities of gas and liquid phases in each flow regime are dictated by the system's thermohydraulic behavior. In fact, the liquid in a two-phase flow can be accelerated to velocities approaching or exceeding vapor velocities. Such high velocities can cause erosion corrosion in equipment and piping systems. In this study, bubble and slug flow patterns were produced by varying the inlet air and water flow rates. The superficial gas velocities ranged from 0.0029 to 0.7042 m/s, while the superficial liquid velocity was varied from 0 to 0.1470 m/s have been tested. The resulting flow types were observed and filmed with a camcorder. Once a sufficient range of inlet conditions has been observed, flow pattern maps of bubble and slug flow could be created for the vertical tube systems. Moreover this thesis also investigated relation between rise velocity of single slug and the slug length, void fraction at different air and water flow rate, rise velocity of continuously generated slugs, and air-lift pump operation within slug flow.
The followings are some background about two-phase flow in a vertical tube.
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