Study on anti-freezing performance of partition water allocation for natural draft wet cooling towers under lateral wind conditions in winter

Cooling towers are indispensable facilities for nuclear power plants, which bear the core functions of residual heat removal and system circulation. In order to prevent the cooling tower from freezing during low load operation in winter, the operational safety of nuclear power plants is improved. In this paper, three partition water allocation schemes are proposed. These schemes divide the heat and mass transfer zones in the tower into multiple sub-regions while keeping the total water inflow volume unchanged. Under lateral wind conditions, the influence of different spray densities on the anti-freezing effect of different partition water allocation schemes was studied. The temperature field, velocity field, gas-water ratio, and cooling performance at the bottom of the fill zone were analyzed. The results show that when the total circulating water volume and the lateral wind velocity are constant, the change of the spray density in the partition can adjust the heat transfer of water and air in the area and achieve complete anti-freezing. When the lateral wind speed is 2 m/s, the spray density in zone I increases from 1.06 kg/(m 2 ·s) to 1.14 kg/(m 2 ·s). In the process, the temperature of the bottom surface of the fill zone for the three water distribution schemes increases by 0.03 °C, 0.04 °C and 0.17 °C, respectively. At the same time, the partition water allocation also leads to the temperature stratification on the bottom surface of the fill zone, with the three-zone water distribution scheme being the most obvious.