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Interfacial force field characterization in a constrained vapor bubble thermosyphon

1995; Wiley; Volume: 41; Issue: 9 Linguagem: Inglês

10.1002/aic.690410913

1547-5905

Sunando Dasgupta, Joel L. Plawsky, Peter Wayner,

Heat Transfer and Boiling Studies

Abstract Isothermal profiles of the extended meniscus in a quartz cuvette were measured in the earth's gravitational field using an image‐analyzing intefferometer thai is based on computaer‐enhanced video microscopy of the naturally occurring ineetference fringes. These profiles are a function of the stress field. Experimentally, the augmented Young‐Laplace equation is an excellent model for the force field at the solid‐liquid‐vapor intrfeces for heptane and pentane menisci on quartz and tetradecane on SFL6. Effects of refractive indices of the solid and liquid on the measurement techniques were demonsrrauzd. Experimentally obtained values of the disjoining pressure and dispersion constantswere compared to those predicted from the Dzyaloshiniskii‐Lifshitz‐Pitaevskii theory for an ideal surface and reasonableagreements were obtained. A parameter introduced gives a quantitative measurement of the closeness of the system to equilibrium. The nonequilibrium behavior of this parameter is also presented.