A numerical investigation of vapor flow in large air-cooled condensers

A numerical simulation method - using a combination of computational fluid dynamics (CFD), numerical and analytical methods - for investigating the nature of the vapor flow distribution in the primary condensers of a large ACC is presented. A definite trend in inlet loss coefficient distribution through the heat exchanger bundles is identified. The vapor flow distribution is found to be influenced by the inlet loss coefficients to such an extent that the flow distribution appears to not conform to the expected pattern typical of parallel or reverse flow manifolds. This non-uniform axial distribution of vapor amongst the primary condenser tubes places an additional demand on the dephlegmator that cannot be overlooked. This verified simulation method can be applied during the design phase of an ACC to improve the steam-side performance of these systems.