POD based modeling on flow and heat transfer of air-cooled condenser influenced by natural wind

Abstract

Numerous factors, including the meteorological and the geographical conditions as well as the configurations of the fin tube bundles, can affect the performance of an air-cooled condenser (ACC) in a power generating unit. In this work a new model is presented to rapidly and accurately predict the flow and heat transfer characteristics of an ACC under the influence of natural wind. This reduced-order model is based on proper orthogonal decomposition (POD) of the three-dimensional velocity and temperature fields and encompasses natural wind directions ranging from 0° to 90°. In the process of operation in the present paper, a combined procedure involving spare and complementary POD is formulated to treat the issue of high nonlinearity associated with the large variable gradients which generate vortices around the ACC. A flux matching procedure is also introduced for estimation of the weight coefficients of the POD modes. The velocity and temperature fields of four typical test cases were estimated with maximum relative errors of 1.75% and 0.19%, respectively. At the same time, the degree of freedom was reduced by 105 compared to calculations made using computational fluid dynamics. The present research may provide a new and more reliable approach to real-time operational control of ACCs in power plants under polytropic natural wind conditions.