Recent works by the authors have shown the high efficiency of using thin liquid films, moving under the action of gas in a flat mini-channel, for removing high heat fluxes. In the present work, we carefully study the total heat losses in such a system. Total heat losses are divided into two portions: heat losses from the heating coil to the atmosphere and heat spreadings from the heater to the substrate. The relative values of the total heat losses prior to the crisis are decreasing with increasing critical heat flux and do not exceed approximately 20% for the critical heat flux between 500 and 900 W/cm2.

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Abstract.Intensively evaporating liquid films, moving under the friction of a co-current gas flow in a mini-channel (shear-driven liquid films), are promising for the use in cooling systems of modern semiconductor devices with high local heat release. In this work, the effect of various parameters, such as the liquid and gas flow rates and channel height, on the critical heat flux in the locally heated shear-driven water film has been studied. A record value of the critical heat flux of 1200 W/cm 2 has been achieved in experiments. Heat leaks to the substrate and heat losses to the atmosphere in total do not exceed 25% for the heat flux above 400 W/cm 2 . Comparison of the critical heat fluxes for the shear-driven liquid film and for flow boiling in a minichannel shows that the critical heat flux is an order of magnitude higher for the shear-driven liquid film. This confirms the prospect of using shear-driven liquid films in the modern high-efficient cooling systems.