Numerical Analysis of Solar Triangular Air Duct with Conical Turbulators

摘要

Solar air heater is a device that converts incoming solar radiation into usable heat energy. But its low heat transfer coefficient is a constraint attached to its widespread use. Disturbance or roughness on the absorber plate creates turbulence in the fluid flow which results in the increase of heat transfer coefficient. In the past, such kinds of investigations have been carried out with different roughness shapes in different shape of ducts. In this paper, a numerical investigation is conducted on a solar triangular air duct with conical protrusion turbulators for a relevant range of Reynolds number and wide geometrical parameters. Commercially available ANSYS FLUENT 18.1 is used to numerically simulate the 3D model of triangular duct with conical turbulators. The SST k-ω model is employed to solve the turbulent flow governing equations as it is found to have good agreement with the empirical formula for flat plate collector. Effect of roughness height, e=0.8-1.7 mm and roughness pitch, P=10-18 mm on dimensionless performance parameters of solar air collector is observed at a wide range of Reynolds number, Re=3000-18000. Sixteen different geometrical configurations are considered for overall investigation. Optimum geometrical configuration of conical turbulators is evaluated.