Can CFD accurately predict the heat-transfer and pressure-drop performance of finned-tube bundles?

• Finned-tube bundles in cross flow were modelled using Computational Fluid Dynamics (CFD).
• The model was used to predict heat-transfer and pressure-drop performance of the bundle.
• Solid; partially-serrated; and fully-serrated, helically-wound fins were investigated.
• Results were found to be within the range predicted by existing empirical correlations.
• Finned-tube performance is highly sensitive to the height/density of fin serrations.

A Computational Fluid Dynamics (CFD) model capable of predicting heat-transfer and pressure-drop performance of finned-tube bundles in cross flow is presented. Three helically-wound fin geometries are investigated: solid (continuous); partially-serrated; and fully-serrated. A steady-state approach, with a two-equation turbulence model, is employed to examine Reynolds numbers in the range of 5000–30,000. The external Nusselt number and overall pressure drop predicted by the CFD model are compared with those predicted by published empirical correlations. The CFD results fall within the range of values predicted by the empirical correlations. The CFD results show that the Nusselt number increases by up to 23% between the partially- and fully-serrated fins; this sensitivity to serration geometry is not captured in any currently published empirical correlations.

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