The micro reacting pipe with 3D internal structure, which is a micromixer with the shape of the pipe, has shown great advantages regarding mass transfer and heat transfer. Since the fluid flow is mostly laminar at the micro-scale, which is unfavorable to the diffusion of reactants, it is important to understand the influence of the geometry of the microchannel on the fluid flow for improving the diffusion of the reactants and mixing efficiency. On the other hand, it is a convenient method to manufacture a micro reacting pipe in one piece through metal additive manufacturing without many post-processing processes. In this paper, a basis for the design of a micromixer model was provided by combining the metal additive manufacturing process constraints with computational fluid dynamics (CFD) simulation. The effects of microchannel structures on fluid flow and mixing efficiency were studied by CFD simulation whose results showed that the internal micro-structure had a significantly positive effect on the mixing efficiency. Based on the simulation results, the splitting-collision mechanism was discussed, and several design rules were obtained. Two different materials were selected for manufacturing with the laser powder bed fusion (L-PBF) technology. After applying pressure tests to evaluate the quality of the formed parts and comparing the corrosion-resistance of the two materials, one material was picked out for the industrial application. Additionally, the chemical experiment was conducted to evaluate the accuracy of the simulation. The experimental results showed that the mixing efficiency of the micro reacting pipe increased by 56.6%, and the optimal determining size of the micro reacting pipe was 0.2 mm. The study can be widely used in the design and manufacture of a micromixer, which can improve efficiency and reacting stability in this field.

中文翻译：

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具有 3D 内部结构的高效微反应管：设计、流动模拟和金属增材制造

内部结构为3D的微反应管，是一种管状的微混合器，在传质和传热方面表现出很大的优势。由于流体流动在微观尺度上多为层流，不利于反应物的扩散，因此了解微通道的几何形状对流体流动的影响对于提高反应物的扩散和混合效率具有重要意义。另一方面，通过金属增材制造一体制造微反应管是一种方便的方法，无需许多后处理过程。在本文中，通过将金属增材制造工艺约束与计算流体动力学 (CFD) 模拟相结合，为微混合器模型的设计奠定了基础。通过CFD模拟研究了微通道结构对流体流动和混合效率的影响，结果表明内部微结构对混合效率有显着的正向影响。基于仿真结果，讨论了分裂碰撞机制，得到了一些设计规则。选择两种不同的材料使用激光粉末床融合 (L-PBF) 技术进行制造。在进行压力测试以评估成型零件的质量并比较两种材料的耐腐蚀性后，挑选出一种材料用于工业应用。此外，还进行了化学实验以评估模拟的准确性。实验结果表明，微反应管的混合效率提高了56.6%，微反应管的最佳确定尺寸为0.2mm。该研究可广泛应用于微混合器的设计和制造，可提高该领域的效率和反应稳定性。