The heat transfer mechanism in Rayleigh-Bénard convection in a liquid with a mean temperature close to its boiling point is studied through numerical simulations with pointlike vapor bubbles, which are allowed to grow or shrink through evaporation and condensation and which act back on the flow both thermally and mechanically. It is shown that the effect of the bubbles is strongly dependent on the ratio of the sensible heat to the latent heat as embodied in the Jakob number Ja. For very small Ja the bubbles stabilize the flow by absorbing heat in the warmer regions and releasing it in the colder regions. With an increase in Ja, the added buoyancy due to the bubble growth destabilizes the flow with respect to single-phase convection and considerably increases the Nusselt number.

Oresta, P., Verzicco, R., Lohse, D., Prosperetti, A. (2009). Heat transfer mechanisms in bubbly Rayleigh-Benard convection. PHYSICAL REVIEW E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS, 80(2), 026304 [10.1103/PhysRevE.80.026304].

Heat transfer mechanisms in bubbly Rayleigh-Benard convection

VERZICCO, ROBERTO;
2009

Abstract

The heat transfer mechanism in Rayleigh-Bénard convection in a liquid with a mean temperature close to its boiling point is studied through numerical simulations with pointlike vapor bubbles, which are allowed to grow or shrink through evaporation and condensation and which act back on the flow both thermally and mechanically. It is shown that the effect of the bubbles is strongly dependent on the ratio of the sensible heat to the latent heat as embodied in the Jakob number Ja. For very small Ja the bubbles stabilize the flow by absorbing heat in the warmer regions and releasing it in the colder regions. With an increase in Ja, the added buoyancy due to the bubble growth destabilizes the flow with respect to single-phase convection and considerably increases the Nusselt number.
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore ING-IND/06 - Fluidodinamica
English
Con Impact Factor ISI
two-phase flows, bubbly rayleigh benard convection
http://pre.aps.org/abstract/PRE/v80/i2/e026304
Oresta, P., Verzicco, R., Lohse, D., Prosperetti, A. (2009). Heat transfer mechanisms in bubbly Rayleigh-Benard convection. PHYSICAL REVIEW E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS, 80(2), 026304 [10.1103/PhysRevE.80.026304].
Oresta, P; Verzicco, R; Lohse, D; Prosperetti, A
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/45882
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