The use of computational fluid dynamics (CFD) in the design and troubleshooting of HRSGs is now well established. However, the large ratio of scales between the overall flow path and the tube bundles themselves means that the bundles must be approximated using “porous media” models, with heat transfer and flow resistance simulated using lumped parameters. The parameters input into these models are taken from the open literature, proprietary data, and/or approximate analytical models. In the case of plain tubes, two-dimensional CFD models have been used to supplement this information. For the finned tubes used in HRSGs, however, 2D models will not suffice and 3D models can quickly become unwieldy. In this work we present the results of a parametric study of pressure drop and heat transfer for finned tube bundles computed using fully three-dimensional CFD models. The results are compared with values computed from correlation equations typically used in design. The advantages and limitations of this approach to obtaining inputs for HRSG tube bundle simulations are discussed.
Matice, Christioher J. and Gao, Brian, “Calculation of Finned Tube Pressure Drop and Heat Transfer Using Fully Three-Dimensional CFD Methods,” Proceedings of EPRI Boiler Tube and HRSG Tube Failures and Inspections International Conference, April 19, 2010, Baltimore, Maryland.