Two-phase modeling of micro-channel critical flows with inlet sub-cooling: A review and benchmark study

Abstract

Micro-channel two-phase critical flow is encountered in the chemical industry and power engineering, such as critical flow leakage/release and two-phase micro-channel heat sinks. Realistic modelling of micro-channel two-phase critical flow deserves enough attention. The paper aims to review the existing two-phase critical flow models and to evaluate the application to simulate the micro-channel critical flow. Choking and critical flow criteria of the single-phase flow and two-phase flow are discussed, and the pressure gradient near the critical cross-section is compared. The development as well as the key characteristic of the critical flow model is drawn on. A benchmark of critical flow models against the experimental data for the micro-channel critical flow, especially for the pressure profile, has been carried out to check the ability of the models to accurately reproduce the micro-channel critical flow, as well to reasonably describe the fluid flow and interfacial transfer. The constitutive relations of existing separated flow models are further compared and evaluated depending on the analysis of the fluid flow and interfacial transfer for two-phase flow to assess constitutive relations. Additionally, the bubble nucleation and metastable liquid property are included in separated flow models to explore the boiling delay in the micro-channel critical flow.