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Bubble dynamics and heat transfer performance on micro-pillars structured surfaces with various pillars heights
- Source :
- International Journal of Heat and Mass Transfer. 163:120502
- Publication Year :
- 2020
- Publisher :
- Elsevier BV, 2020.
-
Abstract
- Micro-pillars structured surfaces have been found to enhance nucleate boiling significantly, as compared with smooth surfaces. In this study, a VOF-based (volume of fluid) numerical model is developed to investigate the single-bubble dynamics on micro-pillars structured surfaces in nucleate boiling, aiming to understand the effect of pillar height (h) on boiling enhancement. The model is solving by the commercial CFD (computational fluid dynamics) solver Fluent. The results show that increasing h modifies remarkably the bubble morphology. An interesting phenomenon is observed for larger h that the bubble bottom undergoes expansion, shrinkage, and re-expansion in gaps between micro-pillars in the growth stage, so that a mushroom-like bubble is generated, with a small root and a large head. The modified bubble morphology promotes the bubble departure, leading to a shorter departure time. Moreover, increasing h also enhances both evaporation rate in the microlayer and evaporation rate on the liquid-vapor interface, and thereby increasing bubble departure diameter. Thus, the shorter departure time and larger departure diameter are responsible for the enhanced boiling heat transfer on micro-pillar structured surfaces with larger h.
- Subjects :
- Fluid Flow and Transfer Processes
Materials science
business.industry
Mechanical Engineering
Bubble
02 engineering and technology
Mechanics
Computational fluid dynamics
021001 nanoscience & nanotechnology
Condensed Matter Physics
01 natural sciences
010305 fluids & plasmas
Boiling
0103 physical sciences
Heat transfer
Volume of fluid method
Fluent
0210 nano-technology
business
Nucleate boiling
Shrinkage
Subjects
Details
- ISSN :
- 00179310
- Volume :
- 163
- Database :
- OpenAIRE
- Journal :
- International Journal of Heat and Mass Transfer
- Accession number :
- edsair.doi...........380da6f0f4030e57f4fa6fa7125c4862