Article révisé par les pairs
Résumé : We analyse pool boiling experiments with single bubbles realized on International SpaceStation (ISS) as part of Reference mUltiscale Boiling Investigation (RUBI). A Fluorinert FC-72 is used as a working liquid. For a fixed liquid pressure between 500 and 1000 mbar, uponinitial thermalization, a joule heater coated atop a transparent BaF2 substrate is on. Following a‘waiting time’ of a few seconds, a pre-prepared nucleation site is activated by a laser pulse. Theresulting bubble growth up to a centimetric size is diagnosed for 9 s by a side-view camera(shape, contact angle) and a bottom-view infrared camera (temperature). While varying thewaiting time and pressure is investigated, we specifically focus on ‘smooth growth’ cases suchas low heater power and near-saturation conditions inasmuch as available in RUBI. Althoughour 500 fps misses a ‘zeroth’ growth stage (the bubble being of a size of hundreds ofmicrometres in the first image it appears), the subsequent (1st, etc.) stages are well explored.Strong shape oscillations, up to detachment, due to an initial explosive growth (1st stage) arefollowed by a quasi-spherical-cap growth (2nd and 3rd stages) with different power laws. Anefficient minimalistic numerical model based on a spherical-cap approximation is developed.This helps to elucidate the physics behind each observation. A strongly disproportionatecontribution of a near-contact-line zone into the evaporation flux is quantified in passing. Upona limited calibration, in conjunction with a classical ‘microregion’ model, the simulationreproduces well the overall measurements including the evaporation contact angle.

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