Development characteristics of drag-reducing surfactant solution flow in a duct
Development characteristics of drag-reducing surfactant solution flow in a duct
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DOI：
10.1007/s00397-003-0335-6
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发表时间：
2004-02
期刊：
影响因子：
2.3
通讯作者：
Hiroshi Suzuki;G. Fuller;T. Nakayama;H. Usui
中科院分区：
文献类型：
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作者：
Hiroshi Suzuki;G. Fuller;T. Nakayama;H. Usui
通过双折射实验测量表面活性剂溶液的时间特性和激光多普勒测速系统测量表面活性剂溶液管道流的流向平均速度分布，研究了稀阳离子表面活性剂溶液流动的发展特性。对于这两个实验，阳离子表面活性剂（油基双羟甲基乙基氯化铵：Ethoquad O/12）的浓度保持恒定在 1000 ppm，水杨酸钠抗衡离子与表面活性剂的摩尔比为 1.5。从双折射实验来看，稀表面活性剂溶液显示出非常长的延迟时间，对应于胶束剪切诱导的结构形成。这导致表面活性剂溶液在管道中的流动发展非常缓慢。即使在距离入口112倍水力直径的测试段末端，流动也没有完全发展，但在管壁上仍然具有发展的边界层特征。从时间特征和边界层发育情况来看，表面活性剂溶液流动充分发育需要1000～2000倍水力直径的入口长度。
Development characteristics of dilute cationic surfactant solution flow have been studied through the measurements of the time characteristics of surfactant solution by birefringence experiments and of the streamwise mean velocity profiles of surfactant solution duct flow by a laser Doppler velocimetry system. For both experiments, the concentration of cationic surfactant (oleylbishydroxymethylethylammonium chloride: Ethoquad O/12) was kept constant at 1000 ppm and the molar ratio of the counter ion of sodium salicylate to the surfactants was at 1.5. From the birefringence experiments, dilute surfactant solution shows very long retardation time corresponding to micellar shear induced structure formation. This causes very slow flow development of surfactant solution in a duct. Even at the end of the test section with the distance of 112 times of hydraulic diameter form the inlet, the flow is not fully developed but still has the developing boundary layer characteristics on the duct wall. From the time characteristics and the boundary layer development, it is concluded that the entry length of 1000 to 2000 times hydraulic diameter is required for fully developed surfactant solution flow.