Numerical simulation study on different spray rates of three-area water distribution in wet cooling tower of fossil-fuel power station

•Three-area water distribution structure of the cooling tower is proposed.•The effect of spray rate vary with location on the outlet temperature is discussed.•A basic experiment is carried out in the field test.•The spray rate with the maximum decrease of the outlet water temperature is given. A coal-burning power plant’s cooling tower can take away about 55% of the heat that the steam absorbs in the boiler, which represents a big energy saving potential. This paper presents a three-dimensional numerical model to analyze the influence of non-uniform water distribution on the cooling performance of a counter-flow wet cooling tower with different spray rates, while providing thermal calculation of a large cooling tower. In addition, the user-defined function in the fill zone is compiled. The heat and mass transfer in the fill zone is solved by UDF. This study covers a three-area water distribution structure in the water distribution system. Cooling tower data verified the accuracy of the model. The influence of the inner, middle and outer areas in relation to their location on the cooling tower and effect on spray rate on the outlet water temperature was investigated in detail. The effect of the three-area water distribution structure on the velocity field, temperature field and the mass fraction of H2O in the tower are analyzed. The water flow rate that makes the temperature drop to its maximum low point has been given. The results show that the outlet water temperature of the tower can be effectively reduced by adopting the three-area water distribution structure and proper water distribution flow. Consequently, it can improve the efficiency of the cooling tower and generate enormous economic benefits.