ABSTRACT
At concentrations critical micelle concentration surfactant molecules dissolved in aqueous solution assemble into colloidal aggregates such as micelles or vesicles, which vary in shape and size depending on system conditions. The self-assembly of surfactant drag reduction (DR) additives (DRAs) permits them to be used in recirculation applications such as in district heating/cooling systems. This chapter reviews the role of giant micelles in surfactant DR, their effects on turbulent structures, their microstructures, their rheological characteristics, and the variables affecting their DR effectiveness along with practical applications. Turbulent flow DR is observed when addition of small amounts of additives such as high polymers or surfactants to a solvent leads to significant reduction in friction energy loss in conduit flows compared to the Newtonian solvent. Among various types of surfactant systems studied for DR, soap-type anionic surfactants such as potassium oleate are effective DRAs with good mechanical stability.
