Study on enhanced heat transfer mechanism for crossflow-counterflow combined mechanical draft cooling tower

This paper proposes a crossflow-counterflow combined mechanical draft cooling tower structure, aiming to reconstruct the flow field within the tower and enhance air-water heat transfer. Through numerical simulation, the study deeply investigates the influence mechanisms of five key parameters (middle zone water-spraying density q₂, outer zone water-spraying density q₃, middle zone water-spraying width L, crossflow filling height H, and crossflow filling width D) on the aerodynamic field and air-water temperature field within the tower, identifying an optimal parameter combination within the study scope. The results showed these parameters significantly affected the aerodynamic field distribution by regulating the balance between ventilation resistance and water-spraying density, thereby optimizing airflow organization. Concurrently, adjustments in the flow field led to adjustments in ventilation rate, which combined with the water-spraying density to reconfigure the air-water temperature field and in turn influenced heat and mass transfer efficiency. Orthogonal analysis obtained the optimized parameter combination: D = 2 m, H = 1 m, L = 1.5 m, q₂ = 3 kg/(m²·s), q₃ = 3 kg/(m²·s). Under this configuration, the circulating water temperature drop reached 12.12 °C, showing a 3.5 % improvement compared to the original counterflow mechanical draft cooling tower, significantly enhancing the thermal performance of the cooling tower. This research provides crucial theoretical foundations and engineering application references for optimizing cooling tower designs.