Optimization design of grooved evaporator wick structures in vapor chamber heat spreaders

This article proposes a novel optimization method for designing the layout of grooved evaporator wick structures in vapor chamber heat spreaders. Firstly, the design is transformed into a general ‘Area-to-Line’ (AL) constructal problem with conductive heat transfer in a disc configuration. Then, constructal optimization of the first order high conductivity channels (HCCs) with strict length scale is carried out based on entransy dissipation rate (EDR) minimization. According to the optimal constructs, the uniformly heated disc is divided into a series of identical sectors whose perimeter is set as the heat sink and other boundaries are all adiabatic. Based on this, a new growth simulator is developed from the inspiration of natural branching phenomena, and applied to obtain the full constructal layouts of the HCCs. In such simulation, the HCCs are described by parameterized level-set surfaces, which start at the heat sink line and grow toward the disc center according to the design sensitivities. The evaporator wick structure derived by growth simulation shows a unique topology exhibiting dichotomous, hierarchical and branching characteristics, which make the capillary pressure improve, and the temperature gradient more homogeneous. The proposed method contributes to the vapor chamber heat spreaders with better thermal performance.