Novel method for improving the cooling performance of natural draft wet cooling towers

Abstract

A novel method for improving the cooling performance of natural draft wet cooling towers (NDWCTs) by installing air ducts in the rain zone was proposed for the first time. To study the effect of air ducts on NDWCTs and the associated mechanism, a 3D numerical model was established. The accuracy and credibility of the NDWCT model were validated. Based on the numerical model, the air temperature uniformity coefficient Cu,θ and the airflow rate G of the tower were computed to evaluate the effect of air ducts on tower aerodynamic field. The tower outlet water temperature t2 was assessed to clarify the effect of air ducts on tower cooling performance. This study found that air ducts improved both the aerodynamic field and the cooling performance of the NDWCT and that the improvement is quite dependent on the crosswind velocity. The optimal effect of air ducts achieved under windless conditions. To determine the effect mechanism of the air ducts, the distributions of air velocity, air-water ratio, air temperature, and water temperature on some representative sections of the tower were analyzed under both windless and crosswind conditions.