Abstract In this study, two novel porous lattice air-cooled heat exchangers (Lattice 1 and Lattice 2) were fabricated by the selective laser melting (SLM) technique from an aluminum alloy (AlSi10Mg) powder. Repetitions of the Rhombi-Octet unit cells of different cell sizes were used to form the porous matrices. Experiments were carried out in a wind tunnel to evaluate the thermal-hydraulic performances of the heat exchangers. The thermal performance indicators such as the overall thermal conductance (UA), air-side thermal resistance (Ra), air-side heat transfer coefficient (ha) and volumetric heat flux density ( q ˙ v ) of the porous lattice heat exchangers were determined and comparisons were made against two conventional fin-tube heat exchangers (Fin-tube 1 and Fin-tube 2). In addition, the pressure drops across the heat exchangers were also measured. Based on our investigations, it was determined that Lattice 1 exhibited approximately 40%–45% higher UA and ha than Lattice 2. However, the pressure drop across Lattice 1 was also higher than Lattice 2. At the same mass flow rate of air ( m ˙ a ), it was found that the ha values of the porous lattice heat exchangers were more than 2 times those of the fin-tube heat exchangers. The significantly higher ha values of the porous lattice are mainly attributed to the presence of interconnected pores and the formation of eddies downstream of the ligaments that improved fluid mixing. For the same pumping power ( W ˙ /H), the use of the porous lattice heat exchangers also resulted in consistently higher ha values than the fin-tube heat exchangers. These results demonstrated the potential of using SLM to fabricate a new generation of commercial-scale compact heat exchangers made of porous lattices. These new porous lattice structures have enhanced the thermal performances of the heat exchanger with no penalty in pumping power.

中文翻译：

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用于空气侧传热增强的增材制造金属多孔晶格换热器

摘要 在本研究中，采用选择性激光熔化 (SLM) 技术从铝合金 (AlSi10Mg) 粉末中制备了两种新型多孔晶格风冷换热器（晶格 1 和晶格 2）。使用不同单元尺寸的 Rhombi-Octet 单元的重复来形成多孔基质。在风洞中进行了实验，以评估换热器的热工水力性能。确定了多孔晶格换热器的总导热系数（UA）、空气侧热阻（Ra）、空气侧传热系数（ha）和体积热流密度（q·v）等热性能指标并与两种传统的翅片管换热器（翅片管 1 和翅片管 2）进行了比较。此外，还测量了热交换器两端的压降。根据我们的调查，确定晶格 1 的 UA 和 ha 比晶格 2 高约 40%–45%。然而，通过晶格 1 的压降也高于晶格 2。在相同的空气质量流量下（ m ˙ a )，发现多孔晶格换热器的 ha 值是翅片管换热器的 2 倍以上。多孔晶格的显着更高的 ha 值主要归因于互连孔的存在和在韧带下游形成的涡流，这些涡流改善了流体混合。对于相同的泵送功率 (W ˙ /H)，使用多孔晶格换热器也导致始终比翅片管换热器更高的 ha 值。这些结果证明了使用 SLM 制造由多孔晶格制成的新一代商业规模紧凑型换热器的潜力。这些新的多孔晶格结构增强了换热器的热性能，而没有泵送功率的损失。