Research progress concerning turbulent drag reduction of surfactant solution

In turbulent flow drag reduction applications, surfactant additive is more applicable than polymer for the flow with high shear or in the closed circulation system due to its reversible mechanical degradation advantage. However, there is not enough understanding of the complicated rheology and drag-reduction mechanism of surfactant solution, limiting its practical application in the drag reduction field. This review introduces the research progress of surfactant drag reduction conducted by the authors in recent years on microstructure, complicated rheology characteristics, turbulent structure, as well as their relations with drag reduction and heat transfer, and analyzes the combined drag reduction effect of surfactant additives in the flow and microgroove fabricated on the wall. The stretch devices can significantly improve the heat transfer performance of surfactant drag-reducing flow with a lower pressure loss penalty. To the shortages of present surfactant drag reduction research, several suggestions are given for the future study. The first is to develop environmentally friendly and effective surfactant, the second is optimal design and layout of heat transfer enhancement device for drag-reducing flow, the third is the study on synergetic effect of drag reduction by combing surfactant drag reduction and other drag-reducing ways, and the final one is practical industrial application research on the scale-up, anticorrosion and persistence effect of surfactant drag reduction.