Determination of some engineering properties of Jojoba granular matter [Simmondsia chinensis]

Jojoba granular matter has received exceptional attention since it contains a unique waxy oil. The Jojoba plant is a promising crop for arid and marginal areas with probable value in combatting desertification and soil degradation in dry regions. This study was carried out to estimate some selected physical, mechanical, and aerodynamic properties of Jojoba grains and provide some essential parameters for modeling their granular flow through computational methods. The considered properties were geometrical dimensions, unit volume, unit mass, thousand-grain weight, projected and surface areas, sphericity, bulk and true densities, porosity, static and dynamic angles of repose, static coefficient of friction, terminal velocity, and drag coefficient. At a moisture content of 6.5%, the Jojoba grain properties significantly reveal strong correlations to the unit mass and length at \(p\le 0.01\), where simple linear equations were developed. From the linear dimensions, the grain shape is considered oval or elongated, with an estimated sphericity of 70%. The results showed that the physical characteristics, such as bulk and true density, were 688 and 831 kg m⁻³, and the average values of unit mass and thousand-grain weight were 0.94 g and 1088.9 g, respectively. The aerodynamic properties of the average terminal velocity and drag coefficient were 18.7 ms⁻¹ and 0. 3, respectively. The rubber surface offered the maximum static coefficient, followed by galvanized steel and Plexiglas in descending order. The mean values of the static and dynamic angles of repose were 40 and 24°, respectively. The obtained data could be necessary for different optimal designs, computational modeling, and development of industrial processes, such as separation, handling, storage, squeezing, sorting, cleaning, harvesting, and post-harvesting.