On the impact of contact line evaporation on bubble growth in microgravity
Cryogenic propellants (H2, CH4, O2) are used for space transportation and must be stored for long periods in micro-gravity (upper stage tanks during ballistic phases, or in future space depot). Variations in temperature and pressure can induce nucleate boiling and cavitation at the wall, with strong consequences for wall heat transfer behaviour and, ultimately, propellant loss. These phenomena are difficult to characterize, not least because of their spatial and temporal multiscale nature. Bubbles have a size of the order of the millimetre, and their growth is driven by phase change, which depends on the thermal boundary layer around the bubble, in the 10 micrometre scale. At the contact line, the nanoregion having a length under the 100 nanometre scale, can have a major impact [2]. Direct numerical simulations, including appropriate modeling for the nanoregion, can be used to study these phenomena at the bubble scale in order to improve our understanding and possibly provide correlations or models for use at larger scales. In the present talk, the numerical approaches developed to study phase change problems with contact lines in incompressible (boiling) and compressible (cavitation) conditions will be revised [3,4,5]. The approach implemented to account for the nanoregion at the subgrid level will be detailed [2]. The seminar will focus on two main applications in micro-gravity, featuring conjugate heat transfer with a wall and contact lines : nucleate boiling in a subcooled liquid [1,6] and pool caviation [7]. Comparison with experimental data and parametric analysis will demonstrate the major impact of the nanoregion in both configurations in terms of heat transfer and bubble shape (apparent contact angle). Eventually, the analysis of the results will allow to extract models for the bubble growth and associated heat transfer flux that are used in large scales simulations featuring multiple bubbles (Figure 1).
References
[1] A Urbano, S. Tanguy and C. Colin, Int. J. of Heat and Mass Trans., 143:118521 (2019)
[2] L. Torres, A. Urbano, S. Tanguy and C. Colin,. J. of Comp. Physics, 497 (2024) 112602
[3] A. Urbano, S. Tanguy, G. Huber, and C. Colin, Int. J. of Heat and Mass Trans,123:1128-1137 (2018)
[4] A. Urbano, M. Bibal, and S. Tanguy. J. Comput. Phys. , 456:111034, (2022).
[5] M. Bibal, M. Deferrez, S. Tanguy and A. Urbano, J. of Comp. Physics, 500 (2024) 112750
[6] L. Torres, S. Tanguy, C. Colin, A. Urbano, Int. J. of Heat and Mass Trans. (http://dx.doi.org/10.2139/ssrn.5274453)
[7] M. Deferrez, S. Tanguy, C. Colin and A. Urbano, Int. J. of Heat and Mass Trans (under review)
Contact Nathanaël Machicoane for more information or to schedule a discussion with the seminar speaker.