ABSTRACT

The fabrication quality of horizontal fluid channels without supports using SLM is low, which further affects friction loss in channels. In the paper, circular fluid channels with diameters from 2 to 14 mm were built horizontally using 316L SS. The surface roughness on the top inner channel is 50–80 μm, while the rest part is approximately 10 μm. The cylindricity is around 0.2 and circularity is 0.16. The fabrication quality was significantly improved using reduced energy input with a compensation model. Friction factor measurements indicate that 75/Re is still valid in laminar flow regardless of fabrication quality. The friction factor in turbulent flow is 0.0034–0.0137, which is higher than the classical theory. Improved fabrication quality slightly reduces the friction factor. A corrected Colebrook model is developed to predict the friction factors for SLM horizontal fluid channels. Building orientation and fluid path need to be considered for reducing pressure loss.

摘要

没有使用SLM的无支撑的水平流体通道的制造质量低，这进一步影响了通道中的摩擦损失。在本文中，使用316L SS水平构建了直径为2至14 mm的圆形流体通道。顶部内部通道的表面粗糙度为50–80μm，其余部分约为10μm。圆柱度为0.2左右，圆度为0.16。使用补偿模型减少了能量输入，大大提高了制造质量。摩擦因数测量表明，无论制造质量如何，75 / Re在层流中仍然有效。湍流中的摩擦系数为0.0034–0.0137，高于经典理论。改善的制造质量会稍微降低摩擦系数。开发了校正的Colebrook模型来预测SLM水平流体通道的摩擦系数。需要考虑建筑物的方向和流体路径以减少压力损失。