Numerical Prediction of Fluid Flow and Heat Transfer in a Circular Tube With Longitudinal Fins Interrupted in the Streamwise Direction

Numerical calculations have been made for the performance prediction of laminar flow through circular tubes with longitudinal fins interrupted in the streamwise direction by arranging them either in a staggered or an in-line manner. Calculations are made for three-dimensional parabolic flow. Due to the repetitive nature of the geometry in the axial direction, the flow exhibits periodically repeating behavior after some initial development length. Calculations have been made for various values of the axial length parameter and two Prandtl numbers for two different fin geometries. Results indicate that in the periodic fully developed regime, for a Prandtl number of 0.7, a tube with staggered arrangement of fins produces less heat transfer enhancement than a tube with continuous fins. A tube with in-line arrangement of fins gives about as much heat transfer augmentation as the tubes with either continuous or staggered fins but with a much less pressure drop penalty. Local quantities such as the axial velocity profiles and the variation of centerline axial velocity give a good physical understanding of the governing phenomena.