PIPE-ESTSC, Friction Factor for 3-D Turbulent Flow in Rough Tubes

1 - Description of program or function: Three-dimensional roughened internally enhanced tubes have been shown to be one of the most energy efficient for turbulent, forced convection applications. However, there is only one prediction method presented in the open literature and that is restricted to three-dimensional sand-grain roughness. Other roughness types are being proposed: hemispherical sectors, truncated cones, and full and truncated pyramids. There are no validated heat-transfer and friction-factor prediction methods for these different roughness shapes that can be used in the transition and fully rough region. This program calculates the Nusselt number and friction factor values, for a broad range of three-dimensional roughness types such as hemispherical sectors, truncated cones, and full and truncated pyramids. Users of this program are heat-exchangers designers, enhanced tubing suppliers, and research organizations or academia who are developing or validating prediction methods. 2 - Method of solution: PIPE obtains solutions of a modified form of the momentum and energy equations using an implicit finite difference method. These modified forms on the momentum and energy equations contain contributions from the roughness elements and also from the unaltered portion of the pipe. 3 - Restrictions on the complexity of the problem: Cannot be used for all types of three-dimensional spiral-rib roughness configurations