A simple multiple flow regime modeling approach of induced flow in external loop airlift reactors

Zupan, Bor (author), Perpar, Matjaž (author), Gregorc, Jurij (author), Šarler, Božidar (author)

Accurate treatment of heat and mass transfer processes inside airlift reactors requires accurate velocity field information. This study presents a novel one-dimensional model forecasting induced liquid flow within an external loop airlift reactor across diverse flow regimes. The approach is grounded on homogeneous flow assumption, augmented by a novel correction term derived through modeling of turbulence-induced pressure losses behind gas structures, employing the separated flow model (Lockhart-Martinelli). The model was assessed by comparing the results with purpose-provided experimental data utilizing air and demineralized water. The gas and liquid superficial velocities ranged from 0.001-0.6 m/s and 0.2–1.1 m/s, respectively. Within ± 10 %, an agreement between the novel model and experimental data was observed for both bubbly, separated, and intermediate flow regimes. A similarly robust agreement was confirmed through comparisons with five published experimental datasets. The distinctive feature of this model is its ability to accommodate multiple flow regimes in a unified manner. It circumvents the necessity for specific regime modeling by introducing a correction term with a complexity marginally surpassing that of the conventional homogeneous flow approach. Beyond its primary application in airlift reactors, the model provides a unified framework for modeling two-phase flow hydrodynamics in thermal applications, particularly in flow boiling and bubble-induced convective heat transfer systems. The model’s simple yet effective structure also allows for integration into higher-fidelity heat transfer simulations, making it valuable for boiling heat transfer studies, enhanced cooling strategies, and industrial multiphase flow applications.

• Language: English
• Keywords: airlift reactor, homogeneous flow, separated flow, theoretical model, induced flow, pressure loss
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: 13 str.
• Numbering: Vol. 272, art. 126410
• PID: 20.500.12556/RUL-168393
• UDC: 544.014:621
• ISSN on article: 1873-5606
• DOI: 10.1016/j.applthermaleng.2025.126410
• COBISS.SI-ID: 232260867
• Publication date in RUL: 11.04.2025

Record is a part of a journal

• Title: Applied thermal engineering
• Publisher: Pergamon Press
• ISSN: 1873-5606
• COBISS.SI-ID: 23195397

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

• Language: Slovenian
• Keywords: vzgonski reaktor, homogeni tok, ločeni tok, teoretični model, inducirani tok, tlačne izgube

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P2-0162
• Name: Večfazni sistemi