Correlations for single-phase convective heat transfer from an array of three-dimensional obstacles in a channel

Empirical correlations are developed to predict the element-averaged convective heat transfer from inline arrays of wall-mounted, three-dimensional protruding heat sources. The composite correlations are based on data from a large database of experiments that covered a wide range of flow rates (chip length-based Reynolds numbers from 600 to 70000), geometries, array spacings, and Prandtl numbers (0.7 to 25.2). The data were obtained from unpublished in-house experiments as well as from a number of studies in the literature. Air, water, and FC-77 (a perfluorinated dielectric liquid) are the coolants considered. A correlation valid for all the fluids is proposed with the Nusselt number as a function of Reynolds and Prandtl numbers, the array spacing, and the channel geometry. A separate correlation is proposed for air data only. The proposed correlations are compared with other predictive formulae in the literature