TY - JOUR

T1 - Investigation of contact line dynamics under a vapor bubble at boiling on the transparent heater

AU - Surtaev, A. S.

AU - Serdyukov, V. S.

PY - 2018/1/1

Y1 - 2018/1/1

N2 - The paper presents the results of an experimental study of dynamics of vapor bubble growth and departure at pool boiling, obtained with the use of high-speed video recording and IR thermography. The study was carried out at saturated water boiling under the atmospheric pressure in the range of heat fluxes of 30−150 kW/m2. To visualize the process and determine the growth rates of the outer bubble diameter, microlayer region and dry spot area, transpa-rent thin film heater with the thickness of 1 μm deposited on sapphire substrate was used in the experiments, and video recording was performed from the bottom side of the heating surface. To study integral heat transfer as well as local non-stationary thermal characteristics, high-speed infrared thermography with a frequency of up to 1000 FPS was used. High-speed video recording showed that after formation of vapor bubble and microlayer region, dry spot appears in a short time (up to 1 ms) under the vapor bubble. Various stages of contact line boundary propagation were ob-served. It was shown that at the initial stage before the development of small-scale perturbations, the dry spot propaga-tion rate is constant. It was also showed that the bubble departure stage begins after complete evaporation of liquid in the microlayer region.

AB - The paper presents the results of an experimental study of dynamics of vapor bubble growth and departure at pool boiling, obtained with the use of high-speed video recording and IR thermography. The study was carried out at saturated water boiling under the atmospheric pressure in the range of heat fluxes of 30−150 kW/m2. To visualize the process and determine the growth rates of the outer bubble diameter, microlayer region and dry spot area, transpa-rent thin film heater with the thickness of 1 μm deposited on sapphire substrate was used in the experiments, and video recording was performed from the bottom side of the heating surface. To study integral heat transfer as well as local non-stationary thermal characteristics, high-speed infrared thermography with a frequency of up to 1000 FPS was used. High-speed video recording showed that after formation of vapor bubble and microlayer region, dry spot appears in a short time (up to 1 ms) under the vapor bubble. Various stages of contact line boundary propagation were ob-served. It was shown that at the initial stage before the development of small-scale perturbations, the dry spot propaga-tion rate is constant. It was also showed that the bubble departure stage begins after complete evaporation of liquid in the microlayer region.

KW - boiling

KW - high-speed visualization

KW - IR thermography

KW - microlayer

KW - phase transitions

KW - LASER INTERFEROMETRIC METHOD

KW - GROWTH

KW - INFRARED THERMOMETRY

KW - MICROLAYER

KW - SPEED IR THERMOGRAPHY

UR - http://www.scopus.com/inward/record.url?scp=85045415260&partnerID=8YFLogxK

U2 - 10.1134/S0869864318010067

DO - 10.1134/S0869864318010067

M3 - Article

AN - SCOPUS:85045415260

VL - 25

SP - 67

EP - 73

JO - Thermophysics and Aeromechanics

JF - Thermophysics and Aeromechanics

SN - 0869-8643

IS - 1

ER -