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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

IMPACT OF SURFACE CHARACTERISTICS ON MICROLAYER, BUBBLE DIMENSIONS AND DEPARTURE IN NUCLEATE BOILING

Get access (open in a dialog) DOI: 10.1615/IHTC16.bae.023121
pages 925-934

Abstract

In this work, an experimental and theoretical investigation about the impact of surface characteristics (wettability and roughness) on the microlayer in boiling process is reported. Stainless steel heaters with five different surface characteristics were employed in the experiment. Laser polishing, wet-etching, and self-assembled monolayer (SAM) coating were applied to control the roughness and wettability of the heater surface. The experiments were carried out in a boiling process on a vertical surface with deionized water at atmospheric pressure. Based on these experimental results, the impact of surface characteristics on the effective microlayer thickness was quantitatively analyzed and formulated. Moreover, after the microlayer is complete evaporated, the dry spot underneath bubble determines the surface tension force of the bubble, which is also investigated in this work. The surface tension force impacts the bubble motions and departure. Consequently, in the paper, the impact of surface characteristics on the microlayer, bubble dynamics and the impact mechanisms are quantitatively analyzed. The understanding and findings from this work will be helpful to improve the modelling of bubble dynamics.