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Início Arquivos Thermal Letter Representantes Futuras reuniões Assembléia das Conferências Internacionais de Transferência de Calor
International Heat Transfer Conference 12

ISSN: 2377-424X (online)
ISSN: 2377-4371 (flashdrive)

Experimental Determination of the Leidenfrost Transition for Water and Aqueous Liquid Mixtures

Chen-Kang Huang
Mechanical Engineering Department University of California at Berkeley, USA

Ali Heydari
Mechanical Engineering Department University of California at Berkeley, USA

Van P. Carey
Department of Mechanical Engineering, University of California Berkeley, CA 94720, U.S.A.

DOI: 10.1615/IHTC12.2360
6 pages

Resumo

This paper summarizes the results of experiments in which the Leidenfrost transition conditions were determined for pure water and a aqueous solutions at atmospheric pressure. These experiments determined Leidenfrost conditions for liquid deposited in fixed volumes on a hot aluminum surface. The experiments specifically focused on aqueous solution at low additive concentration levels for a surface-active alcohol (propanol) that reduces the interfacial tension and increase the vapor pressure. In this investigation, in tandem with more traditional temperature and heat transfer measurements, we explored the use of acoustic recordingin strumentation was to characterize the degree of liquid contact with the solid surface. The results provide insight into the mechanisms of the Leidenfrost transition. Traditionally, this transition has been interpreted as the incipient collapse of the vapor film separatingt he liquid-vapor interface from the solid surface. Experiments indicate that for pure water and aqueous mixtures of the sort considered here, the transition may occur in stages. At very high surface temperatures, the vapor film prevents any liquid contact with the solid. At lower temperatures, the liquid fully wets the surface. At intermediate temperatures, intermittent periods of stable vapor film formation are punctuated by intervals of film collapse and rewetting. Results for pure water and mixtures are summarized and compared to Leidenfrost temperature predictions developed in previous investigations.

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