TY - JOUR

T1 - Interfacial thermal fluid phenomena in shear - Driven thin liquid films

AU - Kabov, Oleg

AU - Zaitsev, Dmitry

AU - Tkachenko, Egor

PY - 2018/1/1

Y1 - 2018/1/1

N2 - The fast development in semiconductor technology is leading to ever higher chip power dissipation and heat fluxes. Recently a novel method of effective cooling, in which heat removal is due to intensive evaporation of a thin liquid film, moving in a flat micro/minichannel under the action of gas or vapor flow has been proposed by the authors. Experimental studies of the flow and destruction of a water film, shear-driven in the channel, under heating from a local heat source with size of 1x1 cm2 has been performed. The influence of liquid and gas flow rates and the channel height (0.17-2.0 mm) on heat transfer and critical heat flux have been investigated. With the help of high-speed imaging it was found that the maximum intensity of heat removal from the heater is achieved in the mode, when the film flow continuity is broken, and the heater is covered with small (of about 100 microns) dry spots with the lifetime of about 1/100 - 1/1000 s; at that the number of spots that exist simultaneously on one square centimeter of the surface can reach several hundreds. Experiments have resulted in the values of heat flux and heat transfer coefficient, which are a record for a thin liquid film (1200 W/cm2 and 300 000 W/m2K, respectively). The values of the critical heat flux are by an order higher than the corresponding values in falling water films. It was found that the use of shear-driven liquid film allows to reach values of CHF several times higher than CHF for flow boiling in the same channel and an order of magnitude higher that CHF for boiling in mini-/microchannels under uniform heating for the same fluid flow rates, but higher length of the heating surface. The CHF values reached are close to the CHF for full evaporation of liquid.

AB - The fast development in semiconductor technology is leading to ever higher chip power dissipation and heat fluxes. Recently a novel method of effective cooling, in which heat removal is due to intensive evaporation of a thin liquid film, moving in a flat micro/minichannel under the action of gas or vapor flow has been proposed by the authors. Experimental studies of the flow and destruction of a water film, shear-driven in the channel, under heating from a local heat source with size of 1x1 cm2 has been performed. The influence of liquid and gas flow rates and the channel height (0.17-2.0 mm) on heat transfer and critical heat flux have been investigated. With the help of high-speed imaging it was found that the maximum intensity of heat removal from the heater is achieved in the mode, when the film flow continuity is broken, and the heater is covered with small (of about 100 microns) dry spots with the lifetime of about 1/100 - 1/1000 s; at that the number of spots that exist simultaneously on one square centimeter of the surface can reach several hundreds. Experiments have resulted in the values of heat flux and heat transfer coefficient, which are a record for a thin liquid film (1200 W/cm2 and 300 000 W/m2K, respectively). The values of the critical heat flux are by an order higher than the corresponding values in falling water films. It was found that the use of shear-driven liquid film allows to reach values of CHF several times higher than CHF for flow boiling in the same channel and an order of magnitude higher that CHF for boiling in mini-/microchannels under uniform heating for the same fluid flow rates, but higher length of the heating surface. The CHF values reached are close to the CHF for full evaporation of liquid.

KW - Boiling and Evaporation

KW - Cooling of microelectronics

KW - Heat transfer enhancement

KW - Two-phase flow

UR - http://www.scopus.com/inward/record.url?scp=85068318144&partnerID=8YFLogxK

U2 - 10.1615/ihtc16.bae.024435

DO - 10.1615/ihtc16.bae.024435

M3 - Conference article

AN - SCOPUS:85068318144

VL - 2018-August

SP - 1061

EP - 1067

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 -