EFFECT OF RELATION BETWEEN MOISTURE CONTENT AND TERMINAL VELOCITY ON WHEAT AND BARLEY GRAINS

Terminal velocity (TV) is one of the important aerodynamic properties of materials, including seeds of agricultural crops that are necessary to design of pneumatic conveying systems, fluidized bed dryer and cleaning the product from foreign materials. Among the properties, terminal velocity is very important. This investigation aimed to provide database about the physical properties (length, width, thickness, volume, percent of sphericity, geometric diameter, arithmetic diameter, transverse surface area and flat surface area) and terminal velocity of crop grains at different moisture contents. Two different grains crop were tested such as wheat grains (Sakha 93-variety) and barley (Giza 130-variety). The wheat and barley grains were tested at different moisture contents of 9, 11, 13, 15 and 17 %. The main results in this study can be summarized as follows: -Length, width, and thickness for wheat grains were 6.18 , 2.80 and 2.21 mm respectively. Meanwhile, length, width, and thickness for barley grains were 9.85, 2.49 and 3.52 mm respectively. -Volumes for wheat and barley were 30.52 and 45.2 mm^3 respectively. -Percents of sphericity for wheat and barley were 62.75 and 44.87% respectively. -Geometric and arithmetic diameters for wheat and barley were 3.88, 4,21 and 4.42, 5.29 mm respectively. -By increasing moisture content of all grains, the terminal velocity increased in general. The highest terminal velocities were 8.53 and 7.8 m/ s for wheat and barley grains respectively at moisture content of 17 %. Meanwhile, the lowest terminal velocities were 7.8 and 6.98 m/ s for wheat and barley grains respectively at moisture content of 9 %.