Determination of moisture-dependent physical and thermal properties of jack bean (Canavalia ensiformis) related to design of processing machines

Abstract

The study was carried out to investigate the effect of the moisture content on physical properties; axial dimension, seed volume, surface area, arithmetic and geometric mean diameter, aspect ratio, sphericity, true and bulk density, angle of repose and static coefficient of friction, and thermal properties; specific heat capacity, thermal conductivity and thermal diffusivity of Jack beans seeds. The properties were evaluated at six levels of moisture ranged from 10.12% to 30.51% d.b. The physical properties are: major, minor and intermediate diameter (19.42 to 20.78mm, 13.92 to 14.59 mm and 13.92 to 14.59 mm), surface area (152.2 to 167.2mm²), seed volume (446.9 to 595.2mm³), arithmetic mean (14.42 to 15.72mm), geometric mean (13.53 to 14.87mm), sphericity (0.696 to 0.716), aspect ratio (0.72 to 0.70), bulk density (0.677 to 0.376 kg/m³), true density ( 0.55 to 0.94 kg/m³), angle of repose (30.63° to 37.18°), static coefficient of friction for each surface (0.417 to 0.625, 0.438 to 0.692 and 0.357 to 0.459) for aluminium, plywood and glass, respectively. The thermal properties are: thermal conductivity (1.5350 to 4.9295 W/mK), thermal diffusivity (2.82 × 10^-5 to 5.63 × 10^-5 m²/s), and specific heat (1.3747 to 1.8912 kJ/kgK). The experimental data were satisfactorily fitted as functions of the moisture content using empirical models. Within the range of moisture levels considered, moisture content exhibits a significant great influence on the studied properties.

Keywords: Axial dimensions, Jack bean, moisture content, physical properties, thermal properties