The geometric shape of a passage's cross-section has an effect on its convective heat transfer capabilities. For concentric annuli, the annular diameter ratio of the annular space plays an important role. The purpose of this investigation was to find a correlation that will ac predict heat transfer coefficients at the inner wall of smooth concentric annuli for turbulent flow of water. Experiments were conducted with a wide range of annular diameter ratios. The Wilson plot method was used to determine annular heat transfer coefficients from which a correlation was developed for annular convective heat transfer.
It was found that the correlation predicted Nusselt numbers accurately within 3% of measured values for annular diameter ratios between 1.7 and 3.2and a Reynolds numbers range, based on the hydraulic diameter, of 4 000 to 30 000.