氯化钠对添加剂水溶液低雷诺数减阻效果的影响

为了改善减阻剂的添加对低雷诺数水流的减阻效果,在试验确认阳离子表面活性剂减阻剂十六烷基三甲基溴化胺(CTAB)减阻特性的基础上,测试氯化钠对CTAB稀薄减阻水溶液在10 mm圆管内低雷诺数水流阻力的改变特性。结果表明:添加氯化钠对表面活性剂CTAB低雷诺数水流确有明显的减阻增强作用;在较高的雷诺数范围内对减阻效果几乎没有影响;在远高于CTAB减阻起始质量分数下,氯化钠的添加才有增强低雷诺数水流减阻效果的作用。氯化钠在低雷诺数下的减阻增强效果随CTAB质量分数和本身添加质量分数的提高均加大,但在CTAB质量分数超过0.05%后,其减阻增强效果明显钝化。在雷诺数约为8 500时,添加0.6%的氯化钠于0.02%CTAB稀薄水溶液中,可使减阻效果由12%增强到26%。

Influence of NaCl on the Drag-reducing Effects in Low Reynolds Number Water Fow with Additive Drag Reducers

In order to improve the drag reduction effects of surfactant dilute aqueous solution at low Reynolds numbers in a pipe flow,experiments has been performed to study how the introduction of a electrolyte Sodium chloride NaCl to surfactant Hexadecyl trimethyl ammonium Bromide CTAB dilute aqueous solution changes the drag reducing characteristics in the flow at low Reynolds numbers in a 10 mm pipe.The results show that adding Sodium chloride NaCl to CTAB surfactant aqueous solutions can significantly enhance the drag reducing effects at lower Reynolds numbers and can little at higher Reynolds numbers,that the enhancing drag-reducing effect by the introduction of NaCl appears only at higher concentrations than the offset concentration of CTAB for drag reduction,and that the effects increase with increasing concentration of CTAB and of NaCl concentration,but it becomes non-significant,as CTAB concentration is higher than 0.08％.By adding 0.6％ NaCl into the 0.02％ CTAB aqueous solution flows,the drag reducing rate is increased from 12％ without NaCl to 26％,at a Reynolds number of 8 500.