Wall slip phenomenon occurs near the inner wall of pipe when dense paste is transported, and it reduces the frictional resistance loss and saves energy. To determine how the boundary layer influences the flowing law, more pipe transporting tests have been performed. Taking coal slime as test material, water and PEO (plasma electrolytic oxidation) were injected into the boundary layer part. Many factors, such as mass concentration, pipe diameter, flow velocity, boundary layer thickness, were systematically studied on their changes influencing pressure loss. The pressure loss decreases exponentially with the increase of boundary layer thickness. Drag reduction effect of PEO as the injecting liquid is better than water, and the pressure loss declines about 20%. The smaller the pipe diameter, lower flow rate, and the more obvious the drag reduction effect will be.

中文翻译：

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边界层如何降低稠密浆体运输中管道阻力降低的进展

输送稠密的糊剂时，在管道内壁附近会发生壁滑现象，从而减少了摩擦阻力损失并节省了能量。为了确定边界层如何影响流动规律，已经进行了更多的管道运输测试。以煤泥为试验材料，将水和PEO（等离子体电解氧化）注入边界层部分。系统地研究了质量浓度，管道直径，流速，边界层厚度等许多因素对压力损失的影响。压力损失随着边界层厚度的增加呈指数下降。PEO作为注射液的减阻效果优于水，压力损失下降约20％。管径越小流速越低