Impact of bubble-induced turbulence on two-phase flow dynamics at high void fraction in a large diameter channel

This study represents the first investigation into the influence of bubble-induced turbulence (BIT) on interfacial area transport mechanisms in gas–liquid two-phase flows under conditions of high void fraction and high velocity in a large diameter channel. Given the unique characteristics of bubble flow in larger channels, the turbulent effects induced by bubbles differ from those observed in smaller channels. However, limited research exists regarding the impact of BIT beyond bubbly flows in large-diameter channels. To address this gap, two approaches for implementing the BIT model are explored: a direct method and an indirect method. This paper assesses both the general and individual effects of BIT. This comparison helps identify the influence of BIT on local distributions of key flow parameters, including turbulent kinetic energy (TKE), turbulent dissipation rate (ε or TDR), void fraction, and interfacial area concentration (IAC). This study further analyzes its impact on the three primary components of the two-group (2G) interfacial area transport equation (IATE) and investigates the coupling mechanisms of two different BIT model approaches and their effects on two-phase flow parameters. The results show that the presence of BIT enhances both TKE and ε (or TDR), resulting in variations in the void fraction and IAC profiles under different flow conditions and for different bubble groups. These findings underscore the importance of incorporating BIT in studies of large-diameter channels, as they enhance the understanding and prediction of gas–liquid flow behaviors.