• An 0.5 mm-thick layered UTVC with different layers number of copper mesh wick was proposed. • Aystematic exploration of the wick ratio and text direction on the heat transfer performance of the layered UTVC. • A mathematical model was established to determine the optimal wick ratio of the layered UTVC. At present, most of the liquid–vapor channel structure of ultra-thin vapor chamber (UTVC) are layered structure, but there is lack of research on the optimization design of layered structure. Therefore, the effect of wick ratio (liquid channel ratio) on the heat transfer performance of the layered structure UTVC is studied experimentally in this paper, the wick ratio is adjusted by changing the number of copper mesh layers. The results show that the maximum heat transfer capacity of UTVC increases first and then decreases with the increase of the number of copper mesh layers. The appropriate number of copper mesh layers can effectively improve the liquid–vapor circulation efficiency of the UTVC and thus improve its heat transfer performance. The maximum heat transfer power of the UTVC with 1, 2, 3 and 4-layer copper mesh are 6.5 W, 8.5 W, 7.5 W, and 4.5 W, respectively. The experimental value of the optimal wick ratio of UTVC is 40%. In addition, a numerical analysis model for the optimal wick ratio with the goal of minimum total pressure drop is established. The calculated optimal wick ratio of the experimental UTVC is 38.94%, and the error with the experimental value is less than 2%. These findings provide critical guidance for layered structure UTVC design optimization.
Yu et al. (Sun,) studied this question.