Design and Modeling of Membrane-Based Evaporative Cooling Devices for Thermal Management of High Heat Fluxes

Abstract

We present a high-heat-flux cooling device for advanced thermal management of electronics. The device incorporates nanoporous membranes supported on microchannels to enable thin film evaporation. The underlying concept takes advantage of the capillary pressure generated by small pores in the membrane, and minimizes the viscous loss by reducing the membrane thickness. The heat transfer and fluid flow in the device were modeled to determine the effect of different geometric parameters. With the optimization of various parameters, the device can achieve a heat transfer coefficient in excess of 0.05 kW/cm 2 -K while dissipating a heat flux of 1 kW/cm 2 . When applied to power electronics, such as GaN high electron mobility transistors, this membrane-based evaporative cooling device can lower the near junction temperature by more than 40 K compared to contemporary single-phase microchannel coolers.

Nanoporous membrane device for ultra high heat flux thermal management

“…5c,d. The solid red and green lines represent our developed models [26][27][28] which capture the conduction resistance in the 650 µm substrate and 2.6 µm supported membrane structure along with the interfacial resistance.…”

“…Previously, we developed a model to predict the overall heat transfer coefficient during evaporation from our suspended membranes [26][27][28] , which accounts for conduction in the substrate, the microchannel support structure, the membrane, and the liquid film, as well as the interfacial transport resistance associated with phase change across the liquid-vapor interface. The intrinsic conductivity at 25°C in the support structure (k ≈ 39 W/mK) and membrane (k ≈ 18 W/mK) were assumed lower than bulk silicon (k ≈ 130 W/mK) due to phonon scattering at small length scales 26 .…”

Numerical investigation of nanoporous evaporation using direct simulation Monte Carlo

“…Traditional cooling techniques [6][7][8][9][10] like pool boiling, flow boiling, and jet impingement have been found to be inadequate for the thermal management of modern electronic devices, as they are only able to handle heat fluxes of the order 100 W/cm 2 . Thin film evaporation [11] enabled by nanoporous membranes is a promising technology that has, in recent years, been proved to be capable of high heat-flux thermal management. The advantage of thin-film evaporation is that it minimizes the thermal resistance across the evaporating liquid and enhances the overall thermal transport, thereby making it possible to achieve a large critical heat flux.…”

“…Nanoporous membranes [15][16][17][18], on the other hand, not only generate high capillary pressure but also minimize the viscous losses as they are very thin, thereby reducing the flow transport length. Optimized semiconductor-based nanoporous membranes have thicknesses of ∼1 μm and pore diameters of L p ∼ 100 nm (e.g., see [11,19]). Additionally, nanoporous membrane-based cooling devices are largely self-regulating in nature since they rely mainly on capillary pressure, p ∼ 2γ R −1 , mediated by surface tension, γ , and the interface radius of curvature, R, to drive the flow.…”

Experimental Investigation of Embedded Micropin-Fins for Single-Phase Heat Transfer and Pressure Drop

“…As the number of chips in the 3D-chip stack is increased, the heat dissipation and thermal conduction resistance to the heat sink (usually at the top) also increase resulting in significant temperature rise and degradation in performance and reliability. The intrachip microfluidic single-or two-phase cooling emerged as a viable solution for 3Dchips architecture and high heat flux applications [5][6][7][8][9][10][11][12][13].…”