Influence of pressure recovery on the performance of an induced draught air-cooled condenser under windless and windy conditions

Abstract

This research aims to enhance the performance of a 20-fan induced draught air-cooled condenser (ACC) by increasing the airflow rate and heat rejection rate of the ACC. These improvements are achieved through pressure recovery, which is the conversion of the dynamic pressure loss at the fan outlets into static pressure. Two different conical diffusers are attached to the outlets of the ACC’s fans to facilitate pressure recovery. The shorter diffuser has a length equal to 20% of the fan diameter and an included angle of 2 θ = 40° ; the longer diffuser is 40% the length of the fan diameter with 2 θ = 32° . The performance of this five-by-four ACC is analysed with and without these diffusers through numerical simulation in OpenFOAM. The analysis is performed under windless and windy conditions. The added diffusers increase the volumetric and thermal effectiveness of the ACC by 2.5% and 2.0%, respectively, under windless conditions. At wind speeds of 3, 6 and 9 m/s, the gain in volumetric effectiveness declines to 1–2%, while the gain in thermal effectiveness varies in the range of 0–5%. The longer of the two diffusers yields greater improvements, especially at higher wind speeds. • Discharge conical diffusers can increase the effectiveness of an induced draught ACC. • Under windless conditions, the mean volumetric effectiveness increases by 2.5%. • Under windless conditions, the mean thermal effectiveness increases by 2.0%. • Under windy conditions, the mean volumetric effectiveness increases by 1–2%. • Under windy conditions, the mean thermal effectiveness increases by 0–5%.