Prediction of behavior of triangular solar air heater duct using V-down rib with multiple gaps and turbulence promoters as artificial roughness: A CFD analysis

Abstract

In the current study, duct of equilateral triangular cross section having V-down ribs with multiple gaps and turbulence promoters as artificial roughness is analyzed and thermo-hydraulic response of duct is measured. For in depth analysis computational fluid dynamics analysis has been carried out using ANSYS FLUENT 19.0. Under the parametric variation part, effect of change in roughness parameters, viz., relative roughness pitch and angle of attack on thermohydraulic performance has been explored. Flow Reynolds number (Re) is systematically varied from 4,000 to 20,000. Proposed roughness proves its worth as its attachment over the absorber leads to an enhancement in Nusselt number and friction factor both, because of enhanced level of interaction among the fluid particles. Study reveals that upon varying the relative roughness pitch (P/e) from 8 to 14 and angle of attack from 45⁰ to 60⁰, maximum heat transfer rate is attained at P/e = 10 and α = 45⁰, respectively, irrespective of Reynolds number. Performance of the SAH with proposed roughness is found to be better than other type of roughness elements studied in recent past.