The cooling tower duct has four main functions: first, it serves as a structural support for the fan; second, it ensures airflow and pressure; third, it ensures the delivery of hot, humid air into the atmosphere, reducing backflow and improving the cooling tower's operating efficiency; and fourth, it acts as a noise reduction mechanism, blocking noise propagation and damping sound energy.
Early ducts were low, right-angled intake ducts, still used by many manufacturers. Their disadvantages include high ventilation resistance and high energy consumption. Second-generation ducts are 11.5-degree inclined diffuser-type kinetic energy recovery ducts with a streamlined intake design. A diffuser section is added above the fan blade rotation surface, which reduces the outlet air velocity, decreasing the dynamic pressure of the hot, humid air entering the atmosphere, thus reducing the fan's total pressure and energy input.
Through the measurement and design of the cooling tower, on-site data is collected, the causes of duct vibration are analyzed, and further computer modeling is used to simulate the cooling tower duct. During the fabrication of the ventilation duct, weak points are reinforced, and the natural frequencies of the cooling tower fan and the ventilation duct are kept within the same resonance range during the selection of the cooling tower. This results in a kinetic energy recovery ventilation duct that effectively prevents vibration of the cooling tower ventilation duct.
