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

A. S. Surtaev, V. S. Serdyukov, I. P. Malakhov

Результат исследования: Научные публикации в периодических изданияхстатьярецензирование

Аннотация

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.

Язык оригиналаанглийский
Страницы (с-по)582-591
Число страниц10
ЖурналJournal of Engineering Thermophysics
Том29
Номер выпуска4
DOI
СостояниеОпубликовано - окт 2020

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