Determination of moisture-dependent physical and thermal properties of jack bean (<i>Canavalia ensiformis</i>) 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