title: Enhanced heat transport by turbulent two-phase Rayleigh-Bénard convection.
abstract: We report measurements of turbulent heat transport in samples of ethane (C2H6) heated from below while the applied temperature difference DeltaT straddled the liquid-vapor coexistence curve T(phi)(P). When the sample top temperature T(t) decreased below T(phi), droplet condensation occurred and the latent heat of vaporization H provided an additional heat-transport mechanism. The effective conductivity lambda(eff) increased linearly with decreasing T(t), and reached a maximum value lambda(eff)(*) that was an order of magnitude larger than the single-phase lambda(eff). As P approached the critical pressure, lambda(eff)(*) increased dramatically even though H vanished. We attribute this phenomenon to an enhanced droplet-nucleation rate as the critical point is approached.
authors.affiliation: Department of Physics and iQCD, University of California, Santa Barbara, California 93106, USA.
authors.forename: Jin-Qiang
authors.initials: JQ
authors.lastname: Zhong
authors.forename: Denis
authors.initials: D
authors.lastname: Funfschilling
authors.forename: Guenter
authors.initials: G
authors.lastname: Ahlers