THERMOHYDRAULIC PERFORMANCE ANALYSIS OF A RECTANGULAR FLUID FLOW CHANNEL WITH A VARIETY OF TURBULENCE GEOMETRIES

The most efficient utilization of energy is of prime concern for every engineering application. The conventional solar air heater, used for many applications and generally of rectangular cross-sections, has very low efficiency. Numerous turbulent geometries have been explored in the literature, each optimized to maximize heat transfer. Optimizing heat transmission by turbulence enhancement also increases the need for pumping power, which should be maintained to a minimum. This investigation has considered three recently investigated turbulent geometries-S-shaped ribs, circular arcs with gaps, and protruded roughness-for the maximum heat transfer rate and the lowest friction factor at various Reynolds number levels. Heat transfer enhancement is found to be a maximum of 5.16 for S-shaped ribs and friction factor enhancement of 4.11 for multiple arcs with gaps from smooth rectangular duct. The thermohydraulic performance parameter at different Reynolds number values for all selected geometries has also been evaluated. A maximum thermal efficiency of 72.8% was observed for multiple arcs with a gap at Re = 21,000. The effective efficiency for the protruded roughness remained comparatively highest for the entire Reynolds number range. The best suitable roughness geometry for different Reynolds number ranges could be selected with the help of this research.