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Bibliographic Details
Main Authors: Mouet, Valentin, Michel, Guillaume, Pétrélis, François, Fauve, Stephan
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2503.08191
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Table of Contents:
  • Rayleigh-B{é}nard convection is investigated with sulfur hexafluoride (SF$_6$) in the vicinity of its critical point. In the supercritical domain, direct measurements of the heat flux $Q$ as a function of the temperature difference $ΔT$ are consistent with the usual scaling laws of single-phase turbulent convection. Along the liquid-vapor coexistence curve, heat fluxes are dramatically enhanced by condensation and boiling. Optical measurements are performed to document the size and velocity of the bubbles. We report $Q(ΔT, ε)$ in both domains, with $ε$ the dimensionless distance to the critical point. Critical scaling laws are observed that can guide the development of theoretical models. In addition, this documents a system of diverging heat transfer coefficient, i.e., in which a significant heat flux can be achieved with an arbitrarily small temperature difference as $ε\to 0$.