Convective Heat Transfer Enhancement for Electronic Device Applications Using Patterned MWCNTs Structures

Abstract

This article reports on the heat transfer characteristics of columnar Vertically Aligned Multiwall Carbon Nanotubes (VA-MWCNTs) grown on a patterned Si surface. In the first part, we describe the procedure for patterning the silicon surface so that the growth of predetermined MWCNTs structures is obtained. The dimensions of CNT structures are in the range of few hundred micrometers while the diameter of single MWCNT was in the range of 30-80 nm. In the second part structures mimicking macroscopic finned heat sinks are used for enhancing forced convective heat transfer on a silicon substrate. Convective heat transfer coefficient has been experimentally measured for silicon substrates with and without MWCNT-based fins on it. The configuration with MWCNTs shows an enhancement in convective heat transfer of 40% and 20%, as maximum and average value respectively, compared to the bare silicon. Experiments have been carried out in a wind tunnel with air as coolant in fully turbulent regime. These encouraging results and the possibility of growing structures directly on silicon can be regarded as a first step towards chip cooling applications based on MWCNT structures.

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“…But enhancements of passive cooling properties were only ∼10–25% so far. The enhancement of heat transfer coefficient of the heat dissipation devices reported here is much more remarkable than that of previous works. − ,, Furthermore, M. I. Shahzad et al have measured the forced convective heat transfer coefficient of silicon surfaces, which range from 48.96 to 179.4 W m –2 K –1 with wind velocity changing from 3.4 to 15.2 m s –1 . Our experimental results demonstrate that the passive cooling devices could even have comparable heat dissipation properties with the active cooling devices.…”

Convective heat transfer enhancement by diamond shaped micro-protruded patterns for heat sinks: Thermal fluid dynamic investigation and novel optimization methodology

“…Novel solutions have been proposed, like innovative pin fin arrays with unusual [8] or non-uniform geometries [9], metal foams [10], dimpled surfaces [11,12,13], porous media [14], micro-protruded patterns [15,16], artificial scale-roughness [17,18] and carbon nanotube based structures [19].…”

Unshrouded Plate Fin Heat Sinks for Electronics Cooling: Validation of a Comprehensive Thermal Model and Cost Optimization in Semi-Active Configuration

“…This optimization strategy considers the heat sink volume, i.e., the amount of material needed to manufacture the part, as the cost index. Consequently, it is suitable to deal with heat sinks manufactured by "Non Subtractive" techniques, both traditional (e.g., extrusion, casting, stamping, folding [13]) and innovative (e.g., additive manufacturing [45,46,49], carbon nanotube bundles [44]) ones.…”