Aerodynamic separation and cleaning of pomegranate arils from rind and white segments (locular septa)

Abstract

In the process of pomegranate arils pneumatic separation, the aerodynamic characteristics of pomegranate aril, rind and locular septa are essential. The main aim of this study was to measure and compare the aerodynamic characteristics of these materials to provide the data and to facilitate the design and adjustment of machines that perform separation of pomegranate arils from rind and locular septa based on aerodynamic characteristics (terminal velocity, drag coefficient and Reynolds number). To achieve this objective, Ashraf variety pomegranate fruit during its maturity stages was studied. The obtained results showed that the variation in maturity stage significantly influenced the terminal velocity, drag coefficient and Reynolds number (P < 0.05). During the fruit maturity, the terminal velocity of locular septa, rind and pomegranate aril increased from 1.05 to 1.16, 3.16 to 3.73 and 5.89 to 6.70 m s−1, respectively. The corresponding value of drag coefficient of the three studied materials decreased from 0.92 to 0.79, 0.75 to 0.59 and 0.53 to 0.36, respectively with advancing fruit maturity. Also these ranges for Reynolds number were 403.24–617.75, 1213.44–1986.37 and 2261.76–3568.02, respectively. Consequently, aerodynamic separation of pomegranate aril from locular septa and rind is theoretically possible if the air velocity value is adjusted according to the terminal velocity of pomegranate aril. Also the obtained equations can be used for calculating the parameters of pomegranate aril movement in pneumatic tunnels or in the design and development of air conveyor and pneumatic separator of pomegranate aril.

Keywords

• Air conveying
• Aerodynamic properties
• Pomegranate aril
• Pneumatic separation
• Physical properties