Experimental and simulation study of pipeline with a divergent crosssection in the pneumatic conveyor of barley seeds

Greenhouse dryers absorb sunlight directly through the transparent coating on the roof of the greenhouse structure. Absorption of pleasant radiation in these dryers is done only from the side where there is sunlight, and it is not possible to absorb pleasant radiation from the opposite side. The purpose of this study is to use a solar parabolic collector to reflect pleasant light on the other side of the dryer to increase the dryer efficiency. For this purpose, the effect of using linear parabolic and point parabolic pleasant collectors and the effect of solar radiation intensity, representing different hours of the day and month in Isfahan, on the speed and temperature of the air inside the chamber of four types of  common greenhouse dryers were evaluated by computational fluid dynamics method. The behavior of hot air flow insidethe dryer was simulated using ANSYS fluent 18 commercial software. The results showed that using solar collectors in greenhouse dryers increased the speed and temperature of the air inside the dryer. Although the point parabolic collector created more localized hot spots in the dryer than the linear parabolic collector, the linear parabolic collector produced a more uniform speed and temperature than the point parabolic collector. Overall, the fourth type ofdryer with a linear parabolic collector had the best performance among the simulated dryers.