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arXiv · 2503.08191

Rayleigh-B{é}nard Convection with Phase Change Close to the Critical Point

Valentin Mouet·Guillaume Michel·François Pétrélis·Stephan Fauve
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Abstract

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 $ε\to 0$.

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Valentin Mouet, Guillaume Michel, François Pétrélis, Stephan Fauve. 2025-03-11. Rayleigh-B{é}nard Convection with Phase Change Close to the Critical Point. https://doi.org/10.1103/physrevlett.134.104001

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