Numerical investigation of flow behavior and film thickness in the single screw expander. (15th January 2021)

• Record Type: Journal Article
• Authors: Liu, Xianfei; Zhang, Hui; Wang, Fang; Xia, Guodong; Li, Zhiqiang; Zhu, Caixia; Zhang, Haofei
• Is Part Of: International journal of mechanical sciences. Volume 190(2021)
• Publication Date: 2021-01-15
• Subjects: Single screw expander -- Liquid film thickness -- Flow behavior -- Curvature ratio -- Dimensionless pitch; Mechanical engineering -- Periodicals; Génie mécanique -- Périodiques; Mechanical engineering; Maschinenbau; Mechanik; Zeitschrift; Periodicals; 621.05
• DOI: 10.1016/j.ijmecsci.2020.106047
• Languages: English
• ISSNs: 0020-7403

Abstract

Highlights: The two-phase flow behavior and film thickness in the vertical helical rectangular channel is investigated using the VOF model. Evolution of velocity profile, pressure contours and liquid holdup distribution is presented as each fluid flows into the helical channel. Relationship between inlet flow angle and liquid distribution in the helical channel is firstly discussed in this paper. Effects of curvature ratio and dimensionless pitch on the film thickness and liquid holdup are demonstrated in details. New relationship between the average liquid film thickness and the liquid holdup is given. Abstract: The need to understand the flow behavior and film thickness in the single screw expander is very crucial since it is known to be a complex system due to the existence of various flow patterns. The present work reports a computational fluid dynamic analysis of two-phase flow behavior and film thickness through a vertical helical rectangular channel using the volume of fluid (VOF) model. The numerical model is validated against available experimental data of annular flow in the helical rectangular channel. The numerical predictions of velocity field, pressure field and liquid phase distribution are presented as each fluid flows into the helical channel. It is found that the inlet flow inclined angle has a significant influence on the liquid film distribution at the outer side of the helical channel. The effects of curvature ratio and dimensionless pitch on the liquid film distribution, film thickness and liquid holdup are illustrated in detail. In addition, the new relationship between the average liquid film thickness and the liquid holdup is also given, and these results are necessary for the optimization design of the single screw expander prototype. Graphical abstract: Paper's novelty: The phase evolution behavior and film thickness in the helical rectangular channel is numerical investigated as each inlet boundary for the gas and liquid is specified by using the VOF model. The evolution of velocity field, pressure fields and liquid distribution is presented as each fluid flows into the helical channel. The effect of inlet flow angle on the liquid distribution in the helical channel is firstly proposed, and the best performance for the liquid film distribution is observed as η= 0.90 β . The effects of curvature ratio and dimensionless pitch on the film thickness and liquid holdup are demonstrated in details, and new relationship between the average liquid film thickness and the liquid holdup is presented. Image, graphical abstract