一种新型两性界面活性剂的减阻特性

对一种新合成的两性界面活性剂N,N,N-三甲胺-N′-油酸酰亚胺在二维通道内的减阻特性进行了实验研究.为了能进行低温测试，以20%的甘醇不冻液为溶剂.溶液质量浓度范围为（5×10^-5）～（1×10^-3），测试温度为-5℃和25℃.用粒子成像测速仪对减阻流动的湍流特性进行了测量.实验表明，这种新型界面活性剂溶液呈现明显减阻特性，且减阻特性与浓度和温度均有很大的关系，最大减阻值可高达83%.该界面活性剂中加入NaNO₂，在低温和低浓度条件下能有效改善减阻效果，而在常温和高浓度条件下反而降低减阻效果.添加界面活性剂抑制了湍流速度脉动和湍流涡脉动，使雷诺剪切应力完全消失.

Drag-reduction characteristics of a novel zwitterionic surfactant solution

Experiments were conducted to study the drag-reduction characteristics of a newly synthesized zwitterionic surfactant solution (oleyl trimethylaminimide) in a two-dimensional channel.Ethylene glycol aqueous solution (EG/W) with mass fraction of 20% was used as solvent for measurements at subzero temperatures.The surfactant mass concentration ranged from 5×10^-5 to 1×10^-3, and the temperature was -5℃ and 25℃ respectively.Turbulence features of the surfactant drag-reducing flow were also measured by using particle image velocimetry (PIV) technique.It was found that the novel zwitterionic surfactant solution showed drag-reduction characteristics which were greatly affected by both concentration and temperature.The maximum drag-reduction could reach 83%.The addition of NaNO₂ to the novel surfactant solution could improve the drag-reduction performance at low temperatures and concentrations, whereas it had a negative effect at high temperatures and concentrations.Turbulent velocity and vortex fluctuations were suppressed and Reynolds shear stress was diminished by adding surfactants into the turbulent flow.