Topology optimization of vapor chamber internal structures consisting of evaporator and condenser

This paper studies the integrated topology optimization of vapor chambers consisting of evaporator and condenser. Firstly, the patterning is regarded as a fundamental access-maximization problem and classified into two general categories: (1) “area to point” (AP) flow problem for condenser wick design and (2) “area to line” (AL) flow problem for evaporator wick design. Then, the branch-patterned disc with first order assembly of flow channels is deduced, where the design domain is divided into 18 identical sectors for both condenser and evaporator. A fluid dynamic model is established to analyze the flow characteristics of the working fluid driven by capillary force. Based on this, a generative topology optimization model with a bifurcation rule is developed to produce the hierarchical capillary flow channels that minimize the global resistance for AP flow problem and AL flow problem, respectively. Unlike the commonly used Eulerian framework for topology optimization, the generative topology optimization used in this paper is carried out essentially in a Lagrangian framework, where capillary flow channels undergoing changes of volume, of positions, of inclined angles and of shapes are described by a set of parameterized level-set surfaces which can move, deform, overlap and merge freely upon the underlying FEM grids. The generated constructal wick structures exhibit dichotomous, hierarchical and branching characteristics. Numerical comparisons show that the new wick structures can contribute to the vapor chambers with better thermal performance.