With the rapid development of electronics, thermal management has become one of the most crucial issues. Intense research has focused on surface modifications used to enhance heat transfer. In this study, multilayer copper micromeshes (MCMs) are developed for commercial compact electronic cooling. Boiling heat transfer performance, including critical heat flux (CHF), heat transfer coefficients (HTCs), and the onset of nucleate boiling (ONB), are investigated. The effect of micromesh layers on the boiling performance is studied, and the bubbling characteristics are analyzed. In the study, MCM-5 shows the highest critical heat flux (CHF) of 207.5 W/cm2 and an HTC of 16.5 W(cm2·K) because of its abundant micropores serving as nucleate sites, and outstanding capillary wicking capability. In addition, MCMs are compared with other surface structures in the literature and perform with high competitiveness and potential in commercial applications for high-power cooling.
Aluminum vapor chambers have become an important component used to solve heat dissipation problems in lightweight applications due to their low density and good heat transfer characteristics. In this paper, a new sintered aluminum powder wick is provided for an aluminum vapor chamber. An aluminum porous wick was sintered using liquid phase sintering technology. Using acetone as the working medium, the influence of the structural parameters of the aluminum wick on its boiling heat transfer performance was studied. The influence of thickness on the boiling heat transfer performance of a sintered porous wick is particularly significant. Thinner, porous wicks have better critical heat flux (CHF). The porosity and particle diameter mainly affect the heat transfer coefficient (HTC). At a low heat flux, the sintered wick with low porosity and a small particle diameter has a higher HTC. The HTC of porous wicks, with a larger particle diameter and porosity, decreases slower. The optimal porosity ranges from 46.4 ± 2.5% to 51.8 ± 2.5%. Compared with the polished aluminum plate, the CHF is increased by 1.7 times, and the HTC is increased by about 4.6 times under the same heat flux.
This work proposed a novel necking heat pipe with double-end heating for thermal management of the overload operation. The addition of another heat load was adopted to obtain a higher threshold critical power for the heat pipe system. The thermal performance of thermal switch heat pipe (TSHP) and traditional grooved heat pipe (TGHP) was investigated experimentally, including the threshold critical power, starting characteristic, recovery characteristic, surface temperature distribution, thermal resistance, etc. The optimized TSHP exhibited a larger threshold critical power range with low additional heat load input (from 55 W to 65 W, almost 20% increase), low starting additional heat load input (2 W), good recovery characteristic (less than 150 s from 75 °C to normal after overload), and low thermal resistance with additional heat load input (less than 0.13 °C/W). These results indicate that the optimized TSHP can offer great potential for the overload operation situation with the additional heat load. Such a novel necking heat pipe with double-end heating can be utilized in heat pipe systems to obtain different thermal performances for complicated working situations, especially for the overload operation situation.