Bhambri Pallavi, Narain Ravin, Fleck Brian
Department of Mechanical Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AL T6G 1H9, Canada.
Department of Chemical & Material Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AL T6G 1H9, Canada.
Polymers (Basel). 2017 Dec 7;9(12):683. doi: 10.3390/polym9120683.
Three different polysaccharides, aloe vera, Tamarind powder and pineapple fibers, are utilized as drag reducing agents in a turbulent flow. Using a Taylor⁻Couette setup, consisting of a rotating inner cylinder, for measuring the drag reduction, a range of Reynolds numbers from 4 × 10⁴ to 3 × 10⁵ has been explored in this study. The results are in good agreement with previous studies on polysaccharides conducted in a pipe/channel flow and a maximum drag reduction of 35% has been observed. Further, novel additives such as cellulose nanocrystals (CNC), surfactants and CNC grafted with surfactants are also examined in this study for drag reduction. CNC due to its rigid rod structure reduced the drag by 30%. Surfactant, due to its unique micelle formation showed maximum drag reduction of 80% at low . Further, surfactant was grafted on CNC and was examined for drag reduction. However, drag reduction property of surfactant was observed to be significantly reduced after grafting on CNC. The effect of Reynolds number on drag reduction is studied for all the additives investigated in this study.
三种不同的多糖，即芦荟、罗望子粉和菠萝纤维，被用作湍流中的减阻剂。本研究使用由旋转内筒组成的泰勒-库埃特装置来测量减阻效果，探索了4×10⁴至3×10⁵范围内的一系列雷诺数。结果与先前在管道/通道流中对多糖进行的研究结果高度一致，并且观察到最大减阻率为35%。此外，本研究还考察了新型添加剂，如纤维素纳米晶体（CNC）、表面活性剂以及接枝有表面活性剂的CNC的减阻性能。由于其刚性棒状结构，CNC使阻力降低了30%。表面活性剂因其独特的胶束形成，在低浓度时显示出最大80%的减阻率。此外，将表面活性剂接枝到CNC上并考察其减阻性能。然而，观察到表面活性剂接枝到CNC上后，其减阻性能显著降低。本研究对所研究的所有添加剂考察了雷诺数对减阻的影响。
