Experimental investigation of oil–water flow in the horizontal and vertical sections of a continuous transportation pipe

A series of experiments were conducted to investigate flow pattern transitions and concentration distribution during simultaneous pipe flow of oil–water two-phase flow through the horizontal and vertical sections. The flowing media applied were white mineral oil and distilled water. Superficial oil and water velocities were between 0 and 0.57 m/s. Flow pattern maps revealed that the horizontal and vertical sections of the pipe lead to different flow pattern characteristics under the same flow conditions. The original contributions of this work are that a transition mechanism for predicting the boundary between oil-in-water (O/W) flow and water-in-oil (W/O) in oil–water two-phase flow was obtained. The effects of input water cut, oil and water superficial velocities on the concentration distribution of the dispersed phase were studied. The empirical formulas for the phase holdup based on the drift-flux model were obtained. The predicted results agreed well with those of the experimental data, especially for the O/W flow pattern.

Simultaneous Measurement of Two-Phase Flow Parameters for Drift-Flux Model

The drift-flux model is widely used in study, calculation and design of two-phase flow. It is a highly efficient model that requires little computation resources. In the model, accurate calculation of the distribution parameter C0 and the drift velocity Vgj is a critically important factor. The calculation requires simultaneously measured data of phase velocity and void fraction distributions or profiles. By using currently widely used methods for two-phase flow measurement, satisfying the requirement is highly difficult. This paper presents novel results of simultaneous measurement of the phase velocity and void fraction profiles in a vertical round tube of 50 mm inner diameter. A combination measurement method has been developed. It comprises the multiwave Ultrasonic Velocity Profile (multiwave UVP) method and the Wire Mesh Tomography (WMT). Based on the measured data, C0 and Vgj have been calculated. They have been compared with those of the published experimental data and correlations. Analyses of the measured data have been carried out. For the first time, the analysis results reveal the variation of C0 and Vgj in the measured flow conditions. More importantly, the data obtained are also useful for the development and validation of the computational codes for two-phase flow.

The Interfacial Area Weighted Area-Averaged Gas Velocity Model for the Interfacial Area Transport Equation in the System Analysis Code

The interfacial area transport equation is a more accurate and stable way to compute the interfacial area concentration than the traditional empirical correlation in the two-phase two-fluid model. And among the parameters in the two-group interfacial area transport equation, the interfacial area concentration weighted area-averaged gas velocity is an important parameter to close the two-group area-averaged interfacial area transport equation in the system analysis code. However, there has been no theory model to compute the interfacial area concentration weighted area-averaged gas velocity until now. So this study established the theory model for two-group interfacial area concentration weighted area-averaged gas velocity based on the drift-flux model for the two-phase dispersed bubble flow. The experimental data were selected from the published literature, which include the detailed two-phase interfacial structure experimental data for the slug bubble flow. The interfacial area concentration weighted area-averaged gas velocity model predicted the selected experimental data well, which validated the developed model. Moreover, the difference between the interfacial area concentration weighted area-averaged gas velocity and the void weighted area-averaged gas velocity is clarified quantitatively for the first time. The theory model developed in this study can be improved and then be used to compute the interfacial area weighted area-averaged gas velocity because it includes the empirical parameter of conventional drift-flux model.