Performance evaluation of solar air heater with novel hyperbolic rib geometry

This paper presents 2D CFD analysis for the evaluation of thermo-hydraulic performance of artificially roughened solar air heater's absorber plate with novel hyperbolic ribs using ANSYS FLUENT 15.0. The motivation for the present study is derived from the fact that formation of eddies across a rib do influence thermo-hydraulic performance of a flat plate solar air heater. The design of hyperbolic ribs is such that it prevents entrapment of eddies facilitating higher heat transfer rate leading to superior thermos-hydraulic performance. The developed model has been validated for smooth (duct without artificial roughness) as well as roughened ducts. The rib profile parameters have been optimized by performing simulation runs by varying roughness height (e) from 0.5 mm to 2 mm and pitch (P) from 10 mm to 20 mm. The optimum performance is achieved for e = 1 mm and P = 10 mm at Re = 6000 The performance of this novel rib is compared with rectangular, triangular and semicircular rib geometries and is found to be the best among all up to Re = 10000.