Structure of thermal boundary layer and heat transfer characteristics in drag reducing flow with surfactant additive

Heat transfer characteristics of a dilute surfactant/water solution in a two dimensional channel has been experimentally investigated. It is known that surfactant solutions do show a large sensitivity of their drag reduction and heat transfer reduction effectiveness on temperature. In the present experiment, the heat transfer at fixed Reynolds number increased three times when temperature increases only 3 deg. Temperature profile measurements in the thermal boundary layer were also made. It was found that high diffusivity layer exists near the wall in the drag reducing thermal boundary layer. The relation with high difussivity layer and heat transfer coefficient is discussed.