PDF(Pubmed)
Abstract：
In the practical application of hydraulic rotating machinery, it is essential to thoroughly explore drag reduction and rheological characteristics of drag-reducing additives to optimize machinery efficiency and reduce equipment consumption. This paper combines simulation and experimental approaches to investigate the drag-reduction performance and rheological properties of drag-reducing additives. Numerical simulations are initially conducted to investigate the shear-thinning properties of drag-reducing fluid and explore variations in drag-reduction rate. Turbulent phenomena characteristics are described by analyzing turbulent statistical quantities. Subsequently, the rheological behaviors of polyethylene oxide (PEO), cetyltrimethyl ammonium chloride (CTAC), and their mixed solutions under different conditions are scrutinized using a rotational rheometer. The findings indicate that the drag reduction effect amplifies as the rheological index n and characteristic time λ decrease. The numerical simulations show a maximum drag reduction rate of 20.18%. In rheological experiments, a three-stage viscosity variation is observed in single drag-reducing additives: shear thickening, shear thinning, and eventual stabilization. Composite drag-reducing additives significantly reduce the apparent viscosity at low shear rates, thereby strengthening the shear resistance of the system.
摘要：
在液压旋转机械的实际应用中,深入探索减阻添加剂的减阻和流变特性，以优化机械效率和降低设备消耗。本文采用模拟和实验相结合的方法，研究了减阻添加剂的减阻性能和流变性能。最初进行了数值模拟，以研究减阻流体的剪切稀化特性并探索减阻率的变化。通过分析湍流统计量来描述湍流现象特征。随后，聚环氧乙烷(PEO)的流变行为，十六烷基三甲基氯化铵（CTAC），使用旋转流变仪仔细检查了它们在不同条件下的混合溶液。研究结果表明，减阻效果随着流变指数n和特征时间λ的减小而增大。数值模拟显示最大减阻率为20.18%。在流变学实验中,在单一减阻添加剂中观察到三级粘度变化：剪切增稠，剪切稀化,和最终的稳定。复合减阻添加剂在低剪切速率下显着降低表观粘度，从而加强了系统的抗剪切能力。
