Turbulent fluid flow, heat transfer and onset of nucleate boiling in annular finned passages

Abstract

An analytical model has been formulated for fully-developed turbulent flow and heat transfer in finned annuli using a modified mixing-length turbulence model. The model accounts for the conjugate heat transfer in the fluid and the solid, and the finite thickness of the fins. Solutions were obtained using the finite element method adopting a mesh that exactly fits the solution domain with fine elements near the solid boundaries. Predictions of the model have been compared with experimental results for smooth and finned annuli with generally good agreement between data and predictions. The model has been extended to predict the conditions at the onset of nucleate boiling using the criterion of Davis and Anderson. Again, these predictions agreed well in magnitude and trend with experimental data of finned annuli.