Numerical modeling to investigate the effect of using a vortex generator and changing the geometry of the solar collector surface on the absorption of solar radiation in a hot water solar dryer

The quality of drying in solar dryers depends on the heat transfer inside the dryer and performance parameters such as pressure drop and efficiency factor. Therefore, the purpose of this research is to investigate the effect of dryer geometry, vortex flow generator, radiation intensity and Reynolds number on heat transfer, pressure drop and performance evaluation coefficient of solar dryer. For this purpose, three different geometries were considered, including a channel with a completely smooth surface, a channel with a curved surface, and a channel with a flow perturber, all three of which were exposed to specific and uniform solar heat flux radiation. For each of the above modes and for Reynolds numbers 3000, 4500, 6000 and 7500 and solar radiation intensities of 700, 800, 900, 1000 and 1100 wat/m2, the amount of average Nusselt number, pressure drop inside the channel and performance evaluation coefficient calculated. The results showed that the use of a vortex generating channel and a channel with concave surface compared to a simple channel increases the amount of heat transfer. Also, as the Reynolds number of the flow increases, while the pressure drop increases, the average Nusselt number also increases.