An Experimental Study on Boiling Phenomenon in a Liquid Layer
2010 (English)In: 7th International Conference on Multiphase Flow - ICMF 2010 Proceedings, International Conference on Multiphase Flow (ICMF) , 2010Conference paper (Refereed)
This work investigates boiling phenomena by means of imaging and characterization of bubble dynamics in the vicinity of the bubble’s nucleation site. A silicon wafer is used as heat transfer surface so that MEMS fabrication can be applied to create artificial cavity for prescribed nucleation site. The well-controlled bubbles growing on such nucleation site can facilitate measurement and observation. High-speed video camera is employed in visualization, and the instantaneous thickness of the liquid layer is recorded by a confocal optical sensor. Tests are first performed on a water layer with the thickness of 7.5mm±0.5mm, and the bubble departure diameter and frequency as well as the transient evolution of bubble diameter and foot size are obtained in isolated bubble regime. Bubble departure diameter enlarges with increasing heat flux, and the measured maximum diameter is around 3.2 mm. With the decrease of the liquid layer thickness to 2 mm, the bubbles are found to remain on the heater surface for a relative long period, with a dry spot initiation under the bubble that becomes rewetted after the bubble bursting. As the water layer thickness decreases further, irreversible dry spot appears, suggesting a minimum “safe” film thickness in the range from 1.2 to 1.9 mm under the tested heat flux range from 26 kW/m2 to 52 kW/m2.
Place, publisher, year, edition, pages
International Conference on Multiphase Flow (ICMF) , 2010.
boiling, liquid film, bubble dynamics, film dynamics
IdentifiersURN: urn:nbn:se:kth:diva-53253OAI: oai:DiVA.org:kth-53253DiVA: diva2:469725
7th International Conference on Multiphase Flow - ICMF 2010
QC 201201132011-12-262011-12-262012-01-13Bibliographically approved