Two-phase flow instabilities: A review

Review of research on flow instabilities in natural circulation boiling systems

Instability, heat transfer and flow regime in a two-phase flow thermosyphon loop at different diameter evaporator channel

Several decades have been spent on the study of flow instabilities in boiling two-phase natural circulation systems It is felt to have a review and summarize the state-of-the-art research carried out in this area, which would be quite useful to the design and safety of current and future light water reactors with natural circulation core cooling With that purpose, a review of flow instabilities in boiling natural circulation systems has been carried out An attempt has been made to classify the instabilities occurring in natural circulation systems similar to that in forced convection boiling systems The mechanism of instabilities occurring in two-phase natural circulation systems have been explained based on these classifications The characteristics of different instabilities as well as the effects of different operating and geometric parameters on them have been reviewed

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Flow Instabilities in Boiling Two-Phase Natural Circulation Systems: A Review

Review of two-phase flow instabilities in macro- and micro-channel systems

An analysis shows that hydrodynamic instabilities of two-phase flow are classified into at least eight types. Three of them are roughly classified into the static or the Ledinegg instability, and other five of them into the dynamic or the density wave instability. Two typical types of instabilities are observed in our experiment, in each type different pressure drop term: gravitational or frictional pressure drop of two-phase flow is found to be the governing term. Classification method of instabilities and its applications are presented.

/pdf/classification-of-two-phase-flow-instability-by-density-wave-h20z9zo509.pdf

Classification of two-phase flow instability by density wave oscillation model.

Two-Phase FLow Instability by Density Head Pressure Drop

Two-Phase Flow Instability Caused by Density Head Pressure Drop

In recent years, an increasing number of offices have actively harvested daylight for the well-being of occupants. However, if large windows are provided for daylight harvesting, the amount of solar heat gain increases, leading to poor energy efficiency and deteriorated indoor environment. Therefore, the objective of this study was to verify the radiant cooling effect of ceiling slits in an office building based on thermally activated building systems to achieve both daylight harvesting and solar removal through field measurements. In this study, the radiant cooling capacity of a slit ceiling and the indoor radiant environment were measured in a research facility in Fukui City, Japan, during spring (March 16–30) and summer (August 17–31) in 2020. 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/2475-8876.12292

Tetsuo Kobori

Papers

Classification of two-phase flow instability by density wave oscillation model.

Two-Phase FLow Instability by Density Head Pressure Drop

Two-Phase Flow Instability Caused by Density Head Pressure Drop

Application of a slit ceiling based on thermally activated building systems in a daylight‐harvesting office space with direct solar radiation