Turbulent flow behavior of surfactant solutions in straight pipes

•The turbulent flow behavior of drag reducing surfactants was investigated.•The effects of concentration, pipe size and surface roughness, and salinity on drag reduction were presented and discussed.•An analytical Fanning friction factor equation for turbulent flow of purely viscous power law fluids was derived.

In this study, the turbulent flow behavior of surfactant test solutions was examined by measuring pressure drop across a straight pipe at various flow rates. The drag reduction character of surfactant solutions was observed to be affected by concentration, pipe diameter, pipe roughness, and solvent type. Higher percent drag reduction occurred at higher concentrations in larger pipes with minimal surface roughness. Surfactant solutions with salt had increased drag reduction due to the presence of longer micelles. In addition, an analytical Fanning friction factor equation was derived for purely viscous power law fluids. Good agreement was observed between predictions and experimental data in the literature with the new equation.