Abstract
The efficient dissipation of localized heat flux by convection is a key request in several engineering applications, especially electronic ones. The recent advancements in manufacturing processes are unlocking the design and industrialization of heat exchangers with unprecedented geometric characteristics and, thus, performance. In this work, laser etching manufacturing technique is employed to develop metal surfaces with designed microstructured surface patterns. Such precise control of the solid-air interface (artificial roughness) allows to manufacture metal heat sinks with enhanced thermal transmittance with respect to traditional flat surfaces. Here, the thermal performance of these laser-etched devices is experimentally assessed by means of a wind tunnel in a fully turbulent regime. At the highest Reynolds number tested in the experiments ( R e L ≈ 16 , 500 ), elliptic scale-roughened surfaces show thermal transmittances improved by up to 81% with respect to heat sinks with flat surface. At similar testing conditions, cones patterns provide an enhancement in Nusselt number and thermal transmittance of up to 102% and 357%, respectively. The latter results are correlated with the main geometric and thermal fluid dynamics descriptors of the convective heat transfer process in order to achieve a predictive model of their performance. The experimental evidence shown in this work may encourage and guide a broader use of micro-patterned surfaces for enhancing convective heat transfer in heat exchangers.
Highlights
IntroductionThe operating temperature of electronic systems, which is usually regulated by proper cooling technologies, influences the length of their trouble-free operation and durability
The heat dissipation in electronic devices has substantial importance because it significantly affects performance, eventually leading to malfunctioning or failures if not correctly managed [1].the operating temperature of electronic systems, which is usually regulated by proper cooling technologies, influences the length of their trouble-free operation and durability
We have experimentally demonstrated that both flat and finned heat sinks can be produced by direct metal laser sintering (DMLS) with controllable surface roughness, and this leads to augmented convective heat transfer coefficients with respect to the typically smooth surfaces obtained by milling or extrusion processes [37,38]
Summary
The operating temperature of electronic systems, which is usually regulated by proper cooling technologies, influences the length of their trouble-free operation and durability. Nowadays, electronic equipment such as microprocessors or batteries produce increasingly higher quantities of waste heat [2,3]. Heat sinks are typically made of copper or aluminum and are designed to maximize the surface in contact with the cooling medium, aiming to optimize the heat exchange These heat exchangers are widely used with high-performing microprocessors [7], high-power semiconductor devices (e.g., power transistors [8]), and optoelectronics (e.g., lasers and light emitting diodes [9]) to dissipate the heat generated during their operation
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