Abstract

MACGREGOR, H. G.  and  JAWUREK, H H. High speed eine laser interferometry technique for microlayer studies in boiling. R&D j. (Matieland, Online) [online]. 1992, vol.8, pp.1-7. ISSN 2309-8988.

During nucleate boiling thin liquidfilms (microlayer s) form beneath the base of bubbles and evaporate into the bubble interiors. An optical technique is described and validated which permits the simultaneous determination of microlayer geometry versus time and the contribution of microlayer evaporation to bubble growth and to boiling heat transfer. Boiling takes place on an electrically heated, transparent tin-oxide coating deposited on a glass plate which forms the floor of the boiling vessel. With laser illumination from beneath the micro-layers reflect interference patterns similar to Newton 's rings. The fringe patterns are recorded by high-speed cine photography. Simultaneously, and on the same film, bubble profiles (and thus volumes) are obtained under white light illumination. Problems concerning calibration, fringe interpretation, and the nature of the error in previous non-laser interferometry studies are identified and resolved. Sample results are presented and discussed.

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