Aerodynamic and some physical properties of sunflower seeds as affected by moisture content

Abstract: The physical and aerodynamic characteristics of seeds can strongly influence their movements in the agricultural machine as well as in the air.  The knowledge of the physical characteristics of particles is essential for the constructors and operators of agricultural machines.  In this research some physical and aerodynamic properties of two Iranian edible seeds of sunflower cultivars (Badami and Doursefid) were studied in the moisture content range from 7% to 30% wet basis (w.b.).  With decrease in moisture content the true density of Badami and Doursefid decreased from 561.02 to 457.29 kg/m3 and 509.35 to 440.50 kg/m3, respectively.  For studying aerodynamic properties (terminal velocity and drag coefficient) the ratio of mass (g) to projected area (cm2) of seeds were considered as K index.  The terminal velocity of both seed decreased with decreasing K index and moisture content.  The highest average terminal velocity was at moisture content of 30% for Badami and Doursefid as 7.08 and 6.97 m/s respectively, and the lowest was at the moisture content of 7% for both seed varieties, as 5.46 and 5.39 m/s respectively.  With decrease in moisture content, drag coefficient tended to increase, so that its value for Badami and Doursefid changed from 0.59 to 0.95 and 0.52 to 0.75 respectively.   Keywords: sunflower seed, physical properties, aerodynamic propertie