RT Journal Article ID 18ec66b1471f4ac0 A1 James, Carl A. A1 Hodge, B. K. A1 Taylor, Robert P. T1 A Validated Procedure for the Prediction of Fully-Developed Nusselt Numbers and Friction Factors in Tubes with Two-Dimensional Rib Roughness JF Journal of Enhanced Heat Transfer JO JEH(T) YR 1994 FD 1994-09-01 VO 1 IS 3 SP 287 OP 304 AB A procedure based on the discrete element method has been developed and validated to compute Fanning friction factors and Nusselt numbers for fully-developed turbulent flow in tubes artificially roughened with two-dimensional, rectangular rib-type roughness elements spaced such that flow separation and reattachment occurs between ribs. The development is presented, and computed results are compared with appropriate experimental data sets from the literature. The method captures the salient features of flow in the hydraulically-smooth, transitionally-rough, and fully-rough flow regimes with no a priori specification of the flow regime. These comparisons indicate that the discrete element roughness method is consistently valid over the following range of rectangular rib geometries: rib-height to hydraulic-diameter ratios from k/D = 0.01 to 0.0625, rib width-to-height ratios from w/k = 1 to 0.254, and rib pitch-to-height ratios from L/k = 10 to 40. PB Begell House LK https://www.dl.begellhouse.com/journals/4c8f5faa331b09ea,5681c3d45f9e5ddd,18ec66b1471f4ac0.html