Abstract:
Because of water saving, the indirect air-cooling tower has been widely used in thermal power generating units in North China. Indirect air-cooling tower is an important cold side equipment of air-cooling generator unit. Its heat transfer efficiency directly affects the operation of the whole generator unit. Therefore, it is important to study the factors that determine the heat transfer efficiency of indirect air-cooling tower. In particular, the ambient crosswind is known to have the greatest influence on its performance. In this research, by using user-defined function (UDF) to calculate the real-time coupling of ambient wind and cooling water temperature, the dual-indirect air-cooling tower system of a Ningxia power plant was simulated in Fluent software. Then, the freezing risk of the system was studied under strong wind conditions in winter. The results show that the coupling calculation model has superior accuracy and with an error of less than 5% comparing to the measured data. Ambient crosswind increases the unevenness of outlet water temperature of each sector, which is mainly manifested as the sharp decrease of outlet water temperature in windward sectors. Reducing the shutters’ opening of the windward sectors increases the cooling water outlet temperature; however, the water temperature of the outlet in the leeward sectors decreases sharply. When the shutters’ opening of windward and leeward sectors are reduced simultaneously, the outlet water temperature of each sector rises and distributes more evenly, and the freezing risk of the whole tower is generally reduced.