Drag-reducing characteristics of cationic surfactant solution flow in copper pipe

The drag-reducing characteristics of a cationic surfaetant solution flow in copper pipe have been investigated experimentally. The tested drag-reducing fluid was an aqueous solution of the cationic surfactant cetyhrimethyl ammonium chloride （CTAC）. The experimental results show that the maximum drag reduction percentage reduces with, the increase of fluid temperature at low concentration of CTAC, such as 100×10^-6 or 150 × 10 ^-6. Furthermore, the concentration and temperature changes of CTAC solution have significant influ- ences on the drag-reducing ability. The drag-reducing effect of CTAC additives shows great potentials in the application in a district heating/cooling （DHC） system, especially for the radiant floor heating （RFH） system.