Impacts of iron rust particle and weak alkalinity on surfactant micelle structure and drag reduction ability

The surfactant drag reduction effect fades away in practical pipe flow mainly due to the weakly alkaline environment and existence of iron rust in solution. Based on our previous work, this phenomenon is further investigated in the present study. Our results show that both impacts of weak alkalinity and iron rust on micelle structure cause a decrease in the surfactant drag reduction ability. The impact of weak alkalinity on the micelle structure is much more direct and powerful compared with that of iron rust, and consequently, there is a big difference in the destroying degrees of the two impacts on the surfactant drag reduction ability. When the factors of weak alkalinity and iron rust coexist in solution, their impacts on the surfactant micelle structure and drag reduction are mutually independent due to their different impact mechanisms. Finally, the methods for eliminating the impact of weak alkalinity and iron rust on surfactant drag reduction performance are provided.