Solar air heater with hyperbolic ribs: 3D simulation with experimental validation

In this paper, 3D CFD simulations have been performed on the hyperbolic rib with parabolic tip using ANSYS FLUENT 15.0. The present work is undertaken on the optimized hyperbolic rib geometry obtained from the 2D CFD analysis recently performed by our group. The results of 3D simulation have been validated with our own experimental results and with existing well established correlations. The model predictions are in good agreement with the Blasius, Dittus Boelter correlations and the experimental results. The range of percentage deviation is less than 5%, which is reasonably good. With an aim to further improve the performance of hyperbolic ribs, the present numerical study is extended to evaluate thermo-hydraulic performance of different rib configurations such as inclined rib, V-shaped and W-shaped. For each arrangement, the rib inclination angle is varied from 30° to 90°.The inclination of rib results in an additional heat transfer enhancement due to flow separation and generation of secondary flow along the ribs. Thermohydraulic performance for V-shaped arrangement with 60° rib inclination is found to be the best at Re = 6000.