Thermal performance of 0.7mm-thick ultra-thin vapor chambers with composite mesh-groove wick

This work presents the performance test results for 140 × 80 × 0.7 mm³ ultra-thin vapor chambers (UTVCs) with a sintered composite mesh-groove wick under a horizontal or reverse horizontal orientation. Also tested are UTVCs with identical form factors but with a sintered two-layer 200 (2×200) mesh wick. These novel copper-water UTVCs simply comprise a top plate etched with arrayed pillars as the condenser and a wicked bottom plate as the evaporator and liquid path. The pillars provide strong structural support, extended condensation area, and direct shortcuts for liquid return. The thickness of the vapor duct forming between the pillars is 0.33 mm. The evaporator is heated by a 30 × 30 mm² dummy heater; the condenser with a footprint of 140 × 80 mm² is cooled by a cold plate with running water of 50 ºC. Under the horizontal orientation, the maximum heat transfer rate for the composite mesh-groove wick reach 487 W, superior to those of 259 W for the 2×200 mesh wick. The minimum vapor chamber resistances are 0.031±0.01 K/W for both kinds of wick. Under the reverse horizontal orientation, the maximum heat transfer rate is slightly decreased but the minimum vapor chamber resistances is slightly improved for both wicks due to the gravity effect.