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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Steady vapor bubbles in rectangular microchannels

Get access (open in a dialog) DOI: 10.1615/IHTC12.2600
6 pages

Аннотация

We consider long steady vapor bubbles in microchannels of rectangular cross-section in which the vapor is produced by a heater element and condenses in cooler parts of the interface. The shape of the liquid-vapor interface is described in the limit of small capillary number for a two-dimensional model in the regime in which the vapor phase fills most of the cross-section of the channel of rectangular cross-section. The equations for interface shape are solved numerically over a range of parameter values with an integral condition requiring the evaporation near the heater to balance condensation in colder areas of the interface. Depending on the temperature, the side walls can be either dry or covered with a liquid film; we identify criteria for these two different regimes. The asymptotic method breaks down in the limit when capillary condensation becomes important near the bubble top and a different approach is used to determine the shape of the bubble in this limit. Solutions here involve localized regions of large mass fluxes, which are asymptotically matched to capillary-statics regions where the heat transfer is negligible.