Influences of dry-wet hybrid rain zone on the heat and mass transfer characteristics of wet cooling towers: A case study

To study the influences of the dry-wet hybrid rain zone (DWHR) on the heat and mass transfer characteristics for the super-large natural draft wet cooling towers (S-NDWCTs) and provide the relevant reference data for the optimal design, a case study is conducted based on the numerical model. The simulation results show that, after adopting the DWHR, the average gas-water ratio on the bottom of the fillings increases by 4.22%, the volumetric heat transfer coefficient of the fillings zone, rain zone, and spraying zone increase by 1.69%, 2.31%, and 16.1% respectively, on average. Additionally, after adopting the DWHR, the contact heat transfer ratio increases, and the evaporation loss coefficient decreases obviously under the high crosswind speed but changes little under the low or middle crosswind speed. The research can provide an innovative method and theoretical guidance for the design of the S-NDWCTs.