AGH University of Science and Technology, Department of Power Engineering and Environmental Protection, Faculty of Mechanical Engineering and Robotics, Kraków, Poland.
Bioelectrochemistry. 2012 Oct;87:42-9. doi: 10.1016/j.bioelechem.2012.01.011. Epub 2012 Feb 3.
This paper describes the influence of interactions of poly(ethylene oxide) (PEO) with cationic cetyltrimethylammonium bromide (CTAB) micelles on drag reduction. Since the interactions between PEO and CTAB micelles alone are weak, salicylate ions were used as CTAB counterions. They facilitate formation of polymer-micelle aggregates by screening the electrostatic repulsions between the charged surfactant headgroups. The influence of polymer-surfactant interactions on drag reduction is of biomedical engineering importance. Drag reducing additives introduced to blood produce beneficial effects on blood circulation, representing a novel way to treat cardiovascular disorders. PEO is a blood-compatible polymer. However, it quickly mechanically degrades when subjected to high shear stresses. Thus, there is a need to search for other additives able to reduce drag, which would be more mechanically stable, e.g. polymer-surfactant aggregates. Numerical simulations of the flow were performed using the CFX software. Based on the internal structure of the polymer-surfactant solution, a hypothesis explaining the reason of increase of drag reduction and decrease in dynamic viscosity with increasing shear rate was proposed. It was suggested that the probable reason for the abrupt increase in friction factor, observed when the critical Reynolds number was exceeded, was the disappearance of the difference in the dynamic viscosity.
本文描述了聚环氧乙烷（PEO）与阳离子十六烷基三甲基溴化铵（CTAB）胶束相互作用对减阻的影响。由于 PEO 与 CTAB 胶束单独相互作用较弱，所以使用水杨酸根离子作为 CTAB 的抗衡离子。它们通过屏蔽带电荷的表面活性剂头基之间的静电斥力，促进聚合物-胶束聚集体的形成。聚合物-表面活性剂相互作用对减阻的影响具有生物医学工程的重要性。引入血液中的减阻添加剂对血液循环产生有益的影响，代表了一种治疗心血管疾病的新方法。PEO 是一种与血液相容的聚合物。然而，当它受到高剪切应力时，它会迅速机械降解。因此，需要寻找其他能够降低阻力的添加剂，这些添加剂的机械稳定性更高，例如聚合物-表面活性剂聚集体。使用 CFX 软件对流动进行了数值模拟。基于聚合物-表面活性剂溶液的内部结构，提出了一个假设，解释了减阻率随剪切率增加而增加和动态粘度随剪切率增加而降低的原因。当超过临界雷诺数时，观察到摩擦系数的突然增加，其可能的原因是动态粘度的差异消失。
