Determination of Physical Properties, Moisture Absorption Process and Aerodynamic Properties of Grain and Cluster Straw of Two Wheat Cultivars

In this study, physical properties of grain and cluster straw including geometric dimensions, moisture absorption and aerodynamic properties of two wheat cultivars were investigated. The effect of cultivar on width, thickness, geometric diameter, spheroid coefficient and mass density was significant at 1% probability level whilst there were no significant effect on grain projected area, length and weight. Moisture absorption of the grains was rapid during the first 30–40 min and then turned to zero. The terminal velocity of wheat grain and straw in three shapes was measured by calculating the projected area in horizontal, lateral and perpendicular directions and then, the drag coefficient was obtained by the equilibrium of the gravity and drag forces at the terminal velocity. Results also showed that increasing moisture content resulted in an increase in the terminal velocity and a decrease in the drag coefficient. Results obtained in this study can be used in designing wheat- cluster straw separation and processing.