Bubble lift-off diameter of lifting-off and ejecting bubbles in subcooled flow boiling
| Autor: | In Yeop Kang, Yeon-Gun Lee, Il Woong Park, Jia Yu |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
education.field_of_study
geography geography.geographical_feature_category Materials science Atmospheric pressure General Chemical Engineering Bubble Population Mechanics Condensed Matter Physics Inlet Atomic and Molecular Physics and Optics Physics::Fluid Dynamics Subcooling Lift (force) Heat flux Flow boiling education |
| Zdroj: | International Communications in Heat and Mass Transfer. 129:105727 |
| ISSN: | 0735-1933 |
| DOI: | 10.1016/j.icheatmasstransfer.2021.105727 |
| Popis: | The prediction of flow boiling is essential owing to its broad applications and complexity. However, the characteristics of flow boiling have not been fully elucidated. In particular, the selection of a model for the bubble lift-off diameter on which the evaporative heat flux is described by a cubic dependence remains ambiguous. In this study, we measure the bubble lift-off diameter on a flat heated surface in a vertical square channel under subcooled flow boiling conditions. Experiments are performed at the atmospheric pressure for mass fluxes of 75–200 kg/m2s, heat fluxes of 50–300 kW/m2, and an inlet subcooling degree of 4.5 K using demineralized water. Bubbles are categorized into lifting-off and ejecting bubbles based on their detaching behaviors from the wall. More than 1600 bubbles are analyzed to measure the lift-off diameter and lift-off velocity. The experimental results show a significant difference in the bubble lift-off diameter between the two types of bubbles mentioned above. We propose a modified model of the bubble lift-off diameter that can predict the average size based on the population ratio of each group. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect