Evaporation Resistance of Grooved Wicks Fabricated Using Laser Powder Bed Fusion

As electronic devices become more powerful and compact, they generate higher heat fluxes, which can lead to reduced performance and failure if not properly managed. Two-phase cooling systems, such as heat pipes and vapour chambers, are highly effective at dissipating heat from electronic components, using the latent heat of vaporization to transfer large amounts of heat with minimal temperature difference. The design of the wick structure used inside two-phase heat transport technologies is important for thermal and hydraulic performance: The wick sustains the working fluid circulation and is a dominant contributor to the thermal resistance at the evaporator and condenser regions. Recently, additive manufacturing (AM) technologies, such as laser powder bed fusion (LPBF), have been leveraged to develop improved heat pipe technologies in terms of overall device form factor and to fabricate integrated AM wick structures. In the current study, four grooved wicks were developed using the LPBF process by modifying the laser hatch spacing of the process, resulting in wicks with two different groove heights (0.6 and 0.8 mm) and two different groove widths (200 and 300 mu m). These hatched grooved wicks were fabricated by changing the laser hatch spacing between 0.42 and 0.52 mm, with zero angle rotation between layers. Alsi10Mg powder material was used to fabricate the wicks. The evaporator wick thermal resistance was measured in a thermal-hydraulic testing apparatus under saturated vapor conditions and capillary-fed liquid flow through the tested wicks. Results showed a minimum thermal resistance of 0.115 K/w for the hatched wick with a groove height of 0.8 mm and a groove width of 300 mu m. In addition, the same hatched wick achieved the highest heat input flux of 43.5 W/cm(2).