Abstract Flat heat pipes serve as a promising thermal management solution to rapidly increasing miniature heat sources dissipating tremendous power. The operational limit of flat heat pipes is contingent on the wick structure handling high heat fluxes from multiple heat sources, like the CPU and GPU. Given the significance of the wick, this study proposes a novel modified flat heat pipe employing a composite wick structure with two internal wick geometries, straight and convex-shaped. Two segmentation strategies covering the possible arrangements of composite wicks, such as domain and zone-based segmentation are studied. The preliminary investigation commences by comparing the two wick geometries and consequently obtaining the best-performing composite wick arrangement. Further, a parametric study based on the effect of primary-to-secondary wick volume ratio and variable porosity on the key performance parameters is conducted. Based on the evaluation of wall temperature distribution, thermal resistance, equivalent thermal conductivity, pressure variation, and temperature-pressure index, the best wick configuration is concluded. The findings of the study infer that the proposed convex wick profile outperforms both straight wicks and conventional flat heat pipes. A configuration of primary-powder-secondary-fiber convex wick attains a 10% decrement in surface evaporator temperature. A 10:90 configuration attains 151% enhancement in equivalent thermal conductivity. For the same ratio, a porosity of 0.57 minimizes 60% of thermal resistance against a conventional flat heat pipe. The temperature-pressure index of the proposed wick configuration is found to be 0.56.
Avishek et al. (Sat,) studied this question.