Development of Research on Interfacial Area Transport

Abstract

Interfacial area concentration and its transport model are quite important in two-fluid model analysis of gas-liquid two-phase flow, which is widely used for the thermal hydraulic analysis of nuclear reactors. Recent developments and the present status of research on interfacial area transport model were reviewed. The definition and rigorous formulation of interfacial area concentration were introduced. Based on this rigorous formulation, basic transport equations of interfacial area concentration were developed by several research groups. In the interfacial area transport equation, source and sink terms of interfacial area concentration are important, and detailed analyses of these terms were carried out, and constitutive equations based on bubble coalescence, bubble breakup, phase change, bubble expansion, and shrinkage due to pressure change were developed. These interfacial area transport equations and constitutive equations were installed in two-fluid model codes and the validities of these models were confirmed by experimental data. Experimental research studies on interfacial area concentration and its transport were also reviewed. Measurement methods of interfacial area concentration were reviewed and multiple-sensor probe methods were established and commonly used in experimental research. Considerable experimental works have been carried out for air-water two-phase flows, and detailed measurements of distributions on interfacial area concentration and their development in the flow direction were reported. For boiling twophase flow, experimental works on interfacial area concentration and its transport have been carried out and data are being accumulated. These data are used for the validation of interfacial area transport models.

Characterization of horizontal air–water two-phase flow in a round pipe part II: Measurement of local two-phase parameters in bubbly flow

“…Thus, in order to provide closure to the two-fluid model (Ishii and Hibiki, 2006), an accurate description of the interfacial structure is required. Therefore, in view of providing dynamic closure relations to the two-fluid model, the development of the interfacial area transport equation (IATE) has been a critical area of research in recent years (Ishii and Kim, 2004;Ishii et al, 2009;Kataoka, 2010). Dynamic prediction of the interfacial area concentration (a i ) is achieved through mechanistic models for bubble breakup and coalescence processes.…”