This paper reports heat transfer enhancement of forced internal single-phase flow enabled by additively manufactured internally finned channels. We consider internal liquid coolant flow through a tube with constant heat flux applied to the exterior surface. A genetic algorithm was developed and used to optimize the fin geometry in order to minimize total thermal resistance for laminar flow or convection thermal resistance for turbulent flow. The genetic algorithm sampled more than 500 fin geometries, evaluated thermal resistance, and selected the optimum fin geometry. We selected three designs for experimental testing: a complex fin structure suggested by the genetic algorithm; a straight fin design; and a smooth circular channel as a reference. The devices were made from aluminum silica (AlSi10Mg) using direct metal laser sintering additive manufacturing. The devices were tested using a water ethylene glycol mixture (80:20) over the hydraulic diameter based Reynolds number range of 400 – 18,000, covering both laminar and turbulent flow regimes. Finite element simulations of heat transfer and pressure drop helped to understand and interpret the measurements. Compared to the smooth pipe reference design, the total thermal resistance of the genetically optimized fin design was 77% lower for laminar flow at Re_h = 2,000 and 65% lower for turbulent flow at Re_h = 10,000. Compared to the straight fin design that is commonly used for enhancing convection heat transfer in internal flows, the total thermal resistance of the genetically optimized fin design was 55% lower for laminar flow at Re_h = 2,000 and 29% lower for turbulent flow at Re_h = 10,000. We explore the potential design space for different types of heat exchangers by investigating how total heat transfer varies with exterior heat transfer coefficient and channel wall thermal conductivity. This research shows how shape optimization and additive manufacturing can result in devices with improved internal convection heat transfer.

本文报告了由增材制造的内部翅片通道实现的强制内部单相流的传热增强。我们考虑通过管子的内部液体冷却剂流动，其外表面具有恒定的热通量。开发了一种遗传算法并用于优化翅片几何形状，以最小化层流的总热阻或湍流的对流热阻。遗传算法对 500 多个翅片几何形状进行采样，评估热阻，并选择最佳翅片几何形状。我们选择了三种设计进行实验测试：遗传算法建议的复杂鳍结构；直鳍设计；和光滑的圆形通道作为参考。这些器件由硅铝 (AlSi10Mg) 使用直接金属激光烧结增材制造制成。这些设备使用水乙二醇混合物 (80:20) 在基于水力直径的雷诺数范围 400 – 18,000 内进行测试，涵盖层流和湍流状态。传热和压降的有限元模拟有助于理解和解释测量结果。与光滑管道参考设计相比，基因优化翅片设计的总热阻对于 Re 处的层流降低了 77% 传热和压降的有限元模拟有助于理解和解释测量结果。与光滑管道参考设计相比，基因优化翅片设计的总热阻对于 Re 处的层流降低了 77% 传热和压降的有限元模拟有助于理解和解释测量结果。与光滑管道参考设计相比，基因优化翅片设计的总热阻对于 Re 处的层流降低了 77% 对于 Re _h  = 10,000 时的湍流，_h = 2,000 和 65% 。与通常用于增强内部流动中的对流传热的直翅片设计相比，基因优化翅片设计的总热阻对于 Re _h  = 2,000 的层流降低 55%，对于 Re _h = 2,000 的湍流降低 29% _h  = 10,000。我们通过研究总传热如何随外部传热系数和通道壁热导率变化，探索不同类型换热器的潜在设计空间。这项研究展示了形状优化和增材制造如何改善内部对流热传递的设备。