Design and modeling of a high flux cooling device based on thin film evaporation from thin nanoporous membranes

Abstract

Heat dissipation is a limiting factor in the performance of integrated circuits, power electronics and laser diodes. State-of-the-art solutions typically use air-cooled heat sinks, which have limited performance owing to the use of air. One of the promising approaches to address these thermal management needs is liquid vapor phase-change. In this thesis, we present a study into the design and modeling of a cooling device based on thin film evaporation from a nanoporous membrane supported on microchannels. The concept utilizes the capillary pressure generated by the small pores to drive the liquid flow and largely reduces the viscous loss due to the thinness of the membrane. The interfacial transport has been re-investigated where we use the moment method to solve the Boltzmann Transport Equation. The pore-level transport has been modeled coupling liquid transport, vapor transport and the interfacial balance. The interfacial transport inside the pore also serves as a boundary condition for the device-level model. The heat transfer and pressure drop performance have been modeled and design guidelines are provided for the membrane-based cooling system. The optimized cooling device is able to dissipate 1 kW/cm² heat flux with a temperature rise less than 30 K from the vapor side. Future work will focus on more fundamental understanding of the mass and energy accommodation at the liquid vapor interface.