Application research of drag reducing agents in closed circulating water systems

Adding drag reducing agents to closed circulating water system can effectively reduce the energy consumption of circulating cooling water pump, but the existing researches on the effect of drag reducing agents on heat transfer are not well understood. The effects of concentration, Reynolds number and inlet water temperature on the drag reduction（DR） and heat transfer reduction （HTR）of a drag reducing agent (CCTDRA) in the closed circulating water system are analysed. The results show that larger DR and relatively small HTR can be obtained when Re is 11 817 and the volume fraction is 0.30%. In the inlet water temperature range of 25 to 55 ℃, the DR is 46.37% to 48.27%, and the HTR is 9.72% to 13.76%. However, by increasing the flow rate to the maximum power consumption of the pump (82 W), the HTR is still 8.89% to 12.34%, indicating that the drag reducing agent can not completely make up for the heat transfer effect on the heat exchanger even if the water pump is not energy-saving. At this time, it is not feasible for the drag reducing agent to be used in the closed circulating water system.