Heat Transfer Estimation of Turbulent Flow With Surfactant Base on the Coherent Fine Scale Eddy

Experiments for heat transfer and friction drag of turbulent water flow with surfactant have been conducted to investigate the relations between heat transfer and drag reduction and coherent fine scale eddies in near-wall turbulence. Experiments were conducted for several different concentrations of surfactant solution and for several pipes (4m long) with different diameters. In the case of high concentration conditions (500 and 750ppm), the range of drag reduction without heat exchange, increases with the increase of temperature for low temperature region (< 313K), which is irrespective of the concentration. On the other hand, in high temperature region (> 313K), the drag reduction range depend on the concentration, and higher concentration leads to larger drag reduction range. The time scale of coherent fine scale eddies well characterizes the range of heat transfer and drag reduction, simultaneously. As the fluid near the wall is cooled in the heat exchanging process, the heat transfer reduction range is suppressed for the high temperature and high concentration conditions.