Effect of atmospheric wind on natural convection based solar air heaters.

Abstract A detailed numerical investigation is carried out in this work to understand the effect of atmospheric wind on the heat transfer in natural convection based solar air heaters. A 3D inclined rectangular channel has been considered for the numerical simulations. The top wall of the channel is maintained at constant heat flux condition, and other walls of the channel are assumed to be adiabatic in all simulations. The effect of surface radiation between the channel walls and channel walls to the atmosphere is also considered. All the inner surface of the walls of the channel are assumed to be black and the emissivity (ε) of the plates are taken to be 0.95. Numerical simulations are carried out by varying the values of heat flux, q" = 250, 500 and 750 W/m2 , velocity of the atmospheric wind V wind = 0.0, 0.2, 0.6, and 1.0 m/s, and the inclination angle of the channel θ = 15°, 30°, 45°, and 60°. In the parametric study, various directions of free stream flow are also considered such as cross flow over the channel, in the main flow direction of the channel and the diagonal to the channel. In this paper, it is found that external wind imparts significant effects on the heat transfer and flow pattern of the air inside the solar air heater channel. Highlights • Atmospheric wind effect on natural convection based solar air heater is studied. • Atmospheric wind effect is significant at high angle of inclination of the channel. • Effect of surface radiation is significant between the walls of solar air heaters. [ABSTRACT FROM AUTHOR]