TY - JOUR

T1 - Features of Boiling Heat Transfer at Various Pressures on Hydrophilic/Hydrophobic Surfaces

AU - Surtaev, A. S.

AU - Serdyukov, V. S.

AU - Malakhov, I. P.

N1 - Funding Information: The work was supported by the Russian Science Foundation (project no. 18-79-00078). The high-speed visualization was carried out within the framework of the Program of Fundamental Scientific Research of the Russian Academy of Sciences for 2013–2020 (theme III.18.2.3, reg. no. AAAA-17-117030310025-3). Publisher Copyright: © 2020, Pleiades Publishing, Ltd. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2020/10

Y1 - 2020/10

N2 - The effect of surface wettability and pressure on multiscale heattransfer characteristics at liquid boiling was studied. The experimentswere carried out at saturated water boiling on surfaces with differentwettability in the pressure range of 8.8–103 kPa. The usage oftransparent ITO film heater deposited on a sapphire substrate andhigh-speed visualization showed the nucleation site density to reducewith decreasing pressure and to significantly increase on heaters withhydrophobic fluoropolymer coatings. The results on the vapor bubblegrowth rate, bubble emission frequency, and evolution of the triplecontact line at spreading of dry spots are also analyzed in detail. Inparticular, the rate of dry spot growth on a hydrophilic surface wasshown to have a non-monotonic dependence with the lower extremum atpressures in the range of 22–42 kPa depending on the heat flux. Theusage of high-speed infrared thermography enabled measurement of thetemperature field of the heating surface and determination of the heattransfer rate at boiling depending on the pressure and surfacewettability. The heat transfer was shown to decrease with the pressureat boiling on hydrophilic heaters, whereas it can be significantlyenhanced due to a hydrophobic coating at atmospheric pressure in therange of low heat fluxes.

AB - The effect of surface wettability and pressure on multiscale heattransfer characteristics at liquid boiling was studied. The experimentswere carried out at saturated water boiling on surfaces with differentwettability in the pressure range of 8.8–103 kPa. The usage oftransparent ITO film heater deposited on a sapphire substrate andhigh-speed visualization showed the nucleation site density to reducewith decreasing pressure and to significantly increase on heaters withhydrophobic fluoropolymer coatings. The results on the vapor bubblegrowth rate, bubble emission frequency, and evolution of the triplecontact line at spreading of dry spots are also analyzed in detail. Inparticular, the rate of dry spot growth on a hydrophilic surface wasshown to have a non-monotonic dependence with the lower extremum atpressures in the range of 22–42 kPa depending on the heat flux. Theusage of high-speed infrared thermography enabled measurement of thetemperature field of the heating surface and determination of the heattransfer rate at boiling depending on the pressure and surfacewettability. The heat transfer was shown to decrease with the pressureat boiling on hydrophilic heaters, whereas it can be significantlyenhanced due to a hydrophobic coating at atmospheric pressure in therange of low heat fluxes.

UR - http://www.scopus.com/inward/record.url?scp=85099781674&partnerID=8YFLogxK

U2 - 10.1134/S1810232820040062

DO - 10.1134/S1810232820040062

M3 - Article

AN - SCOPUS:85099781674

VL - 29

SP - 582

EP - 591

JO - Journal of Engineering Thermophysics

JF - Journal of Engineering Thermophysics

SN - 1810-2328

IS - 4

ER -