Abstract Slug frequency is one of the most important parameters for designing industrial installations where intermittent gas-liquid flows could be found. Thus, the literature is found full of various experimental investigations and developed empirical correlations to predict such parameter. Nevertheless, the effect of intermittent flow sub-regimes on slug frequencies remains an open issue, especially in the case of plug flow. Hence, the present work is devoted to providing an update review and analysis of the slug frequency in plug flow case. For this purpose, data from previous experiments have been collected and deeply examined. It was found that the increase in liquid superficial velocity and the decrease in pipe diameter could induce an increase of plug frequency. The comparison between experimental data and the predictions of twenty available empirical models showed that the correlations based on Strouhal number and input liquid fraction are the best ones that predict well the experimental plug frequency. However, each correlation is found to be valid for a limited range close to the data's conditions that were used for its development. As such, and by considering an extended range of the whole available experimental database, a new empirical correlation has been proposed.

中文翻译：

---

气液活塞流的段塞频率：新关联的回顾和发展

摘要 段塞频率是设计工业装置的最重要参数之一，其中可以发现间歇性气液流动。因此，文献中充满了各种实验研究，并开发了经验相关性来预测此类参数。然而，间歇流动子机制对段塞频率的影响仍然是一个悬而未决的问题，尤其是在活塞流的情况下。因此，目前的工作致力于提供对塞流情况下段塞频率的更新审查和分析。为此，收集并深入研究了先前实验的数据。发现液体表观速度的增加和管径的减小会引起堵塞频率的增加。实验数据与20个可用经验模型预测的比较表明，基于Strouhal数和输入液体分数的相关性是最好的预测实验堵塞频率的相关性。然而，发现每个相关性在接近用于其发展的数据条件的有限范围内是有效的。因此，通过考虑整个可用实验数据库的扩展范围，提出了新的经验相关性。