Experimental Investigation of Three-Phase Low Liquid Loading Flow

Abstract

Abstract An experimental study is conducted using a 6-in ID facility to investigate characteristics of three-phase stratified wavy flow in horizontal pipelines. The experiments are conducted under low liquid loading condition, which is very commonly observed in wet gas pipelines. The analyzed flow characteristics include wave pattern, liquid holdup, water holdup, pressure gradient, and wetted wall fraction. The experimental range covers superficial gas velocity, νSg, values of 8-23 m/s, superficial liquid velocity, νSL, values of 1-2 cm/s, and inlet liquid stream water cut values of 0-100%. Differential pressure transmitters, a quick closing valve and pigging system, and a high speed camera are used to acquire the data. The trends of the data with respect to input parameters are investigated. The performances of commonly used models are compared to liquid holdup, pressure gradient and water holdup experimental results. The observed wave patterns include stratified smooth and stratified wavy with 2-D waves, 3-D waves, roll waves, and atomization flow. The transitions between the flow patterns vary as a function of water cut. The trends of pressure gradient, liquid holdup, and water holdup with respect to vSg, vSL, and water cut are observed and interpretations based on physics are provided. The predictions of a transient multiphase simulation software, TUFFP Unified Model v. 2012, Beggs and Brill (1973), Taitel and Dukler (1976), and Xiao et al. (1990) are compared to the acquired experimental data. The results from transient multiphase simulation software, Taitel and Dukler (1976) and Xiao et al. (1990) are in good agreement with experimental liquid holdup and pressure gradient data. But the three-phase water holdup trends are not predicted well. The complicated nature of liquid-liquid interactions in three-phase low liquid loading flow causes higher uncertainties in predictions. The number of experimental three-phase data, especially with larger pipe diameters, is very limited. This paper provides with comprehensive data for three-phase stratified flow for a 6-in ID pipe. In addition, the prediction performance of the commonly used predictive tools in the industry is provided.