A novel ultra-thin vapor chamber with radial-gradient hierarchical wick for high-power electronics cooling

The miniaturization and ever-increasing performance of electronic devices has made the thermal management to be a key bottleneck in their rapid development. In this paper, a novel 2-mm-thick ultra-thin vapor chamber (UTVC) with radial-gradient hierarchical wick was firstly designed and fabricated for high-power electronics cooling. The wick had a sunflower-like shape, in which a radial-gradient hierarchical structure was employed to facilitate the circulation of the working fluid. Systematical studies were conducted under forced water cooling condition in order to fully examine the effects of the cooling water inlet temperature and flow rate on the thermal performance of the UTVC. Moreover, aiming at establishing a benchmark for the evaluation of the heat transfer performance of the UTVC, a comparison study between the UTVC and a pure copper plate with the same dimension was conducted. Results showed that the UTVC could effectively transport a heat load of 420 W (about 186.7 W/cm(2)), attaining a minimum thermal resistance of 0.0531 degrees C/VV. Additionally, at a given heat load of 120 W, both decreasing the cooling water inlet temperature and increasing the cooling water flow rate could distinctly improve the UTVC performance. Finally, compared to copper plate, the proposed UTVC exhibited a relatively higher heat transfer performance, and reduced the thermal resistance by up to 59.2%.