WIT Press


2D BEM Modelling Of A Singular Thermal Diffusion Free Boundary Problem With Phase Change

Price

Free (open access)

Paper DOI

10.2495/BE020471

Volume

32

Pages

15

Published

2002

Size

721 kb

Author(s)

V S Nikolayev & D A Beysens

Abstract

We report a 2D BEM modeling of the thermal diffusion-controlled growth of a vapor bubble attached to a heating surface during saturated pool boiling. The transient heat conduction problem is solved in a liquid that surrounds a bubble with a free boundary and in a semi-infinite solid heater. The heat generated homogeneously in the heater causes evaporation, i.e. the bubble growth. A singularity exists at the point of the triple (liquid-vapor-solid) contact. At high system pressure the bubble is assumed to grow slowly, its shape being defined by the surface tension and the vapor recoil force, a force coming from the liquid evaporating into the bubble. It is shown that at some typical time the dry spot under the bubble begins to grow rapidly under the action of the vapor recoil. Such a bubble can eventually spread into a vapor film that can separate the liquid from the heater, thus triggering the boiling crisis (Critical Heat Flux phenomenon).

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