Gas-liquid two-phase flow patterns and pressure drop of decaying swirling flow inside a horizontal pipe

Gas-liquid two phase swirling flow has been widely used in industry. Its flow pattern is fundamental to investigate the two-phase flow. In this paper, two-phase air-water flow patterns and pressure drop of decaying swirling flow generated by vane-type swirler inside a horizontal pipe have been systematically investigated by visualization experiment. The range of superficial gas phase Reynolds number is 17- 23902, while superficial liquid phase Reynolds number is 12-37871, and gauge pressure is 0.003- 0.17 MPa. The five typical flow patterns in a horizontal swirling flow were characterized based on flow visualizations and fluctuation characteristics of pressure drop signals. Then swirling flow regime map nearby the swirler outlet was proposed. As flow patterns altered along the streamwise direction due to swirl decay, flow pattern maps at different positions were proposed, which indicated the swirling flow patterns gradually transformed to non-swirling flow patterns. Finally, a new model to predict frictional pressure drop of air-water swirling flow inside a horizontal pipe containing vane-type swirler was proposed. This correlation performed well on predicting the frictional pressure drop. (c) 2022 Elsevier Ltd. All rights reserved.