In the present study, a topology optimization method of thermal-fluid-structural problems is researched to design the three-dimensional heat sink with load-carrying capability. The optimization is formulated as a mean temperature minimization problem controlled by Navier-Stokes (N-S) equations as well as energy balance and linear elasticity equations. In order to prevent an unrealistic and low load-carrying design, the power dissipation of the fluid device and the normal displacement on the load-carrying surface are taken as constraints. A parallel solver of multi-physics topology optimization problems is built-in Open Field Operation And Manipulation (OpenFOAM) software. The continuous adjoint method is adopted for the sensitivity analysis to make the best use of built-in solvers. With the developed tool, the three-dimensional (3D) thermal-fluid topology optimization is studied. It is found that the Darcy number, which is suitable for fluid design, may cause severe problems in thermal-fluid optimization. The structural features of 3D thermal-fluid-structural problems are also investigated. The “2D extruded designs” are helpful to improve the structural stiffness, and channels with a larger aspect ratio in high-temperature areas improve the cooling performance.

本文研究了一种热流结构问题的拓扑优化方法，以设计具有承载能力的三维散热器。将该优化公式化为由Navier-Stokes（NS）方程以及能量平衡和线性弹性方程控制的平均温度最小化问题。为了防止不现实且低负荷的设计，将流体装置的功率耗散和在负荷表面上的法向位移作为约束。内置的开放式现场操作与操纵（OpenFOAM）软件是多物理场拓扑优化问题的并行求解器。灵敏度分析采用连续伴随法，以充分利用内置求解器。借助开发的工具，研究了三维（3D）热流体拓扑优化。发现适合流体设计的达西数可能在热流体优化中引起严重的问题。还研究了3D热流体结构问题的结构特征。“ 2D挤压设计”有助于提高结构刚度，并且在高温区域中具有较大长宽比的通道可以改善冷却性能。