Water-saving performance study of water conservation and plume abatement device in wet mechanical draft cooling towers

Abstract

A water-saving cooling tower was proposed in the power plant to save water resources. In this paper, the multiphase flow model and the species transport model in FLUENT software are used to simulate the condensation process of wet air, and the performance of the water-saving device is studied. Comparing the experimental results with the simulation results, the relative error of the cooling tower outlet temperature is 0.15%, and the relative error of the cooling tower outlet humidity is 4.65%. We use the mixture model in the multiphase flow model and the species transport model to consider the wet air as a mixture of air and water vapor and ignore the effect of the liquid film on heat transfer. This modeling approach enables the study of humidity variations in wet air condensation and is suited for studying cooling tower water-saving devices. The study results show that an optimum channel length gives the device the best water-saving performance, with a relative channel length of 0.6. In addition, decreasing the cold air inlet temperature by 12 K reduces the cooling tower outlet humidity by 1 g/kg, while increasing the cold air inlet velocity by 6 m/s leads to a reduction in the cooling tower outlet humidity by 1 g/kg.

Keywords

• Wet mechanical draft cooling tower
• Water saving
• Numerical simulation
• Thermal performance
• Cold channel length