Drag reduction and heat transfer of surfactants flowing in a capillary tube

Pressure drop and heat transfer were measured in fully developed laminar flow in a pipe of inner diameter 1.07 mm in the range of Reynolds numbers 10⩽Re⩽450. The study was performed for water and water–surfactant solution of 530 and 1060 ppm. It was shown that these surfactant solutions increase the pressure drop in adiabatic and diabatic flows. The dependence of friction coefficients as a function of solvent Reynolds number was used to predict the ability of certain surfactant solutions to increase drag in laminar flows.