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Evaporation waves in superheated dodecane

Simões-Moreira, J. R. and Shepherd, J. E. (1999) Evaporation waves in superheated dodecane. Journal of Fluid Mechanics, 382 . pp. 63-86. ISSN 0022-1120. http://resolver.caltech.edu/CaltechAUTHORS:20111220-110817276

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Abstract

We have observed propagating adiabatic evaporation waves in superheated liquid dodecane, C_(12)H_(26). Experiments were performed with a rapid decompression apparatus at initial temperatures of 180–300°C. Saturated dodecane in a tube was suddenly depressurized by rupturing a diaphragm. Motion pictures and still photographic images, and pressure and temperature data were obtained during the evaporation event that followed depressurization. Usually, a front or wave of evaporation started at the liquid free surface and propagated into the undisturbed regions of the metastable liquid. The evaporation wave front moved with a steady mean velocity but the front itself was unstable and fluctuating in character. At low superheats, no waves were observed until a threshold superheat was exceeded. At moderate superheats, subsonic downstream states were observed. At higher superheats, the downstream flow was choked, corresponding to a Chapman–Jouguet condition. At the most extreme superheat tested, a vapour content of over 90% was estimated from the measured data, indicating a nearly complete evaporation wave. Our results are interpreted by modelling the evaporation wave as a discontinuity, or jump, between a superheated liquid state and a two-phase liquid–vapour downstream state. Reasonable agreement is found between the model and observations; however, there is a fundamental indeterminacy that prevents the prediction of the observed wave speeds.


Item Type:Article
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http://dx.doi.org/10.1017/S0022112098003796 DOIUNSPECIFIED
http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=14771PublisherUNSPECIFIED
Additional Information:© 1999 Cambridge University Press. Received 3 February 1997 and in revised form 18 September 1998. Published online: 08 September 2000. The first author thanks CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil, for the financial support and the Department of Mechanical Engineering of Escola Politécnica da Universidade de São Paulo, Brazil, for granting him a leave of absence. This research was carried out at the Graduate Aeronautical Laboratory of the California Institute of Technology and supported by the Powell fund at Caltech. Both authors would like to acknowledge the importance of the ideas of Philip A. Thompson. Philip's vision of compressible fluid dynamics and deep insight into the role of thermodynamics in these flows have had a profound influence on us.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (Brazil)UNSPECIFIED
Caltech Powell FundUNSPECIFIED
Record Number:CaltechAUTHORS:20111220-110817276
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20111220-110817276
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:28536
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:20 Dec 2011 22:18
Last Modified:25 Feb 2014 20:19

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