Heat convection in water can be suppressed by adding a small amount of highly thermophilic nanoparticles. We show that such suppression is not effective when a suspension with uniform concentration of nanoparticles is suddenly heated from below. At Rayleigh numbers smaller than a sample dependent threshold Ra;{*} we observe transient oscillatory convection. Unexpectedly, the duration of convection diverges at Ra;{*}. Above Ra;{*} oscillatory convection becomes permanent and the heat transferred exhibits bistability. Our results are explained only partially and qualitatively by existing theories.

Bistable heat transfer in a nanofluid / Donzelli, Gea; Cerbino, Roberto; Vailati, Alberto. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - STAMPA. - 102:(2009), pp. 104503-104503. [10.1103/PhysRevLett.102.104503]

Bistable heat transfer in a nanofluid

DONZELLI, GIAN PAOLO;
2009

Abstract

Heat convection in water can be suppressed by adding a small amount of highly thermophilic nanoparticles. We show that such suppression is not effective when a suspension with uniform concentration of nanoparticles is suddenly heated from below. At Rayleigh numbers smaller than a sample dependent threshold Ra;{*} we observe transient oscillatory convection. Unexpectedly, the duration of convection diverges at Ra;{*}. Above Ra;{*} oscillatory convection becomes permanent and the heat transferred exhibits bistability. Our results are explained only partially and qualitatively by existing theories.
2009
102
104503
104503
Donzelli, Gea; Cerbino, Roberto; Vailati, Alberto
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/1093130
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