Breaking the Flooding Barrier: New Findings on Gas-Liquid Counter-Current Flow

A. Biton, E. Rabinovich, E. Gilad, “Generalized correlation for onset flooding velocity in vertical channels”, International Communications in Heat and Mass Transfer 138, 2022, 106366, https://doi.org/10.1016/j.icheatmasstransfer.2022.106366.

As scientists, we are always searching for answers to complex problems that can impact the engineering applications we rely on every day. The recent article, “Onset of Flooding in Gas-Liquid Counter-Current Flow in Annular and Rectangular Channels,” by Ph.D. student Almog Biton, Dr. Evgeny Rabinovich from Nuclear Research Center Negev, and Prof. Erez Gilad from Ben-Gurion University, explores a significant problem in the field of fluid dynamics.

The article addresses the issue of flooding due to gas-liquid counter-current flow, which can substantially impact crucial engineering applications such as boilers, heat exchangers, and nuclear reactors. Despite numerous studies on the topic, there remains a notable disagreement on the appropriate definition of the characteristic length regarding the onset flooding velocity in rectangular and annular channels.

To address this problem, Biton et al. measured the onset of flooding velocity in one circular and two different annular channels. They considered channel geometries with an inverse trend between the hydraulic diameter and the average circumference. The authors discovered that the hydraulic diameter is not an appropriate characteristic length for annular and rectangular channels to describe the onset flooding velocity. Instead, the average circumference for the annular channel and channel width for rectangular channels exhibited superior performance.

Biton et al. increased the annular channel’s average circumference or the rectangular channel’s width to increase the flooding air velocity. The authors then derived new Wallis-type generalized relationships based on various channel geometries and dimensions. The novel empirical correlation can be defined regardless of the channel geometry.

Despite the extensive literature on the subject, the study’s findings are significant because they offer insight into a problem that has not been fully resolved. By identifying the most suitable geometric dimension to predict the onset of flooding velocity, Biton et al. provide a valuable contribution to fluid dynamics. Their research may have practical implications for designing and operating critical engineering applications that rely on gas-liquid counter-current flow.

As scientists, we must continue exploring complex problems and seeking answers that can improve our understanding and inform real-world applications. The research conducted by Biton, Rabinovich, and Gilad is an excellent example of innovative and impactful work carried out in our research group at Ben-Gurion University.