TY - JOUR

T1 - Temperature discontinuity and resistance at the liquid-gas interface of thin liquid film and droplet under heating

AU - Gatapova, Elizaveta Ya

AU - Kabov, Oleg A.

N1 - Publisher Copyright: © 2018 International Heat Transfer Conference. All rights reserved.

PY - 2018/1/1

Y1 - 2018/1/1

N2 - The rapid development, miniaturization, and increase in the power density of electronics places to greater emphasis on the performance and limits of today's thermal management solutions. Of great interest to engineers and researchers is the possibility of using ultrahigh-intensity evaporation of thin liquid films. The transition between the continuum and molecular scales for a continuous description of phase transition is still an open challenge. We present new data on measurements of the temperature profile across the liquid-gas interface of a heated thin liquid film and small-sized droplet for different fluids. Microthermocouple with the sensor thickness less than 3 µm is used for measurements. A temperature jump at the liquid-gas interface was clearly detected even for small evaporation rate. This jump was measured for heater temperature varying in the range 23 - 80 ° C at normal atmospheric conditions. We found the increasing of the temperature jump with increasing of the heat flux and evaporation rate. An evolution of the temperature profile with increasing of the heater temperature is obtained. Depending on the ambient condition and type of fluids, the temperature in the gas phase near the liquid-gas interface can be higher or lower than that of the liquid. The temperature profiles with negligible temperature jump at liquid-gas interface are observed for some operating conditions. Finally, we estimate the thermal resistance of thin liquid film and droplet, which is useful for cooling systems such as micro-sized vapor chamber.

AB - The rapid development, miniaturization, and increase in the power density of electronics places to greater emphasis on the performance and limits of today's thermal management solutions. Of great interest to engineers and researchers is the possibility of using ultrahigh-intensity evaporation of thin liquid films. The transition between the continuum and molecular scales for a continuous description of phase transition is still an open challenge. We present new data on measurements of the temperature profile across the liquid-gas interface of a heated thin liquid film and small-sized droplet for different fluids. Microthermocouple with the sensor thickness less than 3 µm is used for measurements. A temperature jump at the liquid-gas interface was clearly detected even for small evaporation rate. This jump was measured for heater temperature varying in the range 23 - 80 ° C at normal atmospheric conditions. We found the increasing of the temperature jump with increasing of the heat flux and evaporation rate. An evolution of the temperature profile with increasing of the heater temperature is obtained. Depending on the ambient condition and type of fluids, the temperature in the gas phase near the liquid-gas interface can be higher or lower than that of the liquid. The temperature profiles with negligible temperature jump at liquid-gas interface are observed for some operating conditions. Finally, we estimate the thermal resistance of thin liquid film and droplet, which is useful for cooling systems such as micro-sized vapor chamber.

KW - Boiling and evaporation

KW - Heat transfer enhancement

KW - Liquid-gas interface

KW - Microscopic measurement

KW - Non-equilibrium

KW - Temperature jump

UR - http://www.scopus.com/inward/record.url?scp=85068332188&partnerID=8YFLogxK

M3 - Conference article

AN - SCOPUS:85068332188

VL - 2018-August

SP - 1479

EP - 1484

JO - International Heat Transfer Conference

JF - International Heat Transfer Conference

SN - 2377-424X

T2 - 16th International Heat Transfer Conference, IHTC 2018

Y2 - 10 August 2018 through 15 August 2018

ER -