Dendritic bubble growth during the sub-atmospheric boiling of water in a narrow vertical channel
Résumé
The bubbles observed during the boiling of water at subatmospheric pressure (a few mbar) behave in a very atypical way compared to under atmospheric pressure. Moreover, the presence of very close walls significantly affects bubble dynamics and interface disturbances like fingering can be observed during growth. Interface perturbations were reported in a phenomenological analysis. Image processing software was developed to process the obtained high resolution camera recordings. Based on this software, physical quantities characterising the bubble are measured for the purpose of a parametric study of the dentritic growth of the bubbles. It appeared that the bubble interfacial velocity , bubble interface acceleration and nucleation immersion depth, related to inertia and hydrostatic pressure, have a significant influence on the fingering occurrence.