Life of a single bubble growing within an electric field in microgravity: some preliminary results of the Reference mUltiscale Boiling Investigation

The experimental outcomes of single bubbles nucleated and growth from a heated surface immersed in an electric field in high-quality microgravity level are presented. Data were obtained between September 2019 and January 2021 from the European experiment known as Reference mUltiscale Boiling Investigation (also multiscale boiling project), in which single bubbles of FC-72 were nucleated on a heated surface, on-board the International Space Station. In the experiments reported here, an electrostatic field is imposed in the boiling region by a washer-shaped electrode, centred above the nucleation site. The bubbles are heavily distorted by the electric stresses; in particular, contact angles and contact line length increase with electric field intensity. In the appropriate conditions, bubbles are continuously and regularly sucked towards the electrode, because they are attracted to regions of weaker electric field. The significant contribution of electro-convection is highlighted by the bubbles growth rate. These preliminary results contribute to the insight of the basics of boiling and show promising opportunities for practical application of electric fields in space