Thermal, physical, and engineering properties of Okra (Abelmoschus esculentus L. (Moench) grown in Nigeria

Abstract

As a result of lack of information about the thermal, physical and engineering properties of okra gown in Nigeria some of these properties were studied in order to contribute to the database for properties related to grading, handling, packaging, transportation, cleaning, processing, storage and other futuristic processing units. The study showed that the thermal conductivity, specific heat capacity, latent heat and thermal diffusivity were 0.26 Wm-1K-1, 1.77 KJKg-1K-1, 16.75 KJKg-1 and 0.06×10-7m2s-1 respectively. The mean values of length, width, thickness, arithmetic mean diameter, geometric mean diameter, equivalent diameter, surface area, volume, sphericity and coefficient of contact surface of okra seeds were 6.58 mm, 4.75 mm, 2.37 mm, 4.56 mm, 4.20 mm, 4.33 mm, 55.44 mm2, 38.80 mm3, 63.83% and 63.97% respectively. While the aspect ratio, flakiness, 1000 seed mass, bulk density, true density and porosity were 72.19%, 49.89%, 47.43g, 0.61, 0.62, and 27.00% respectively. The study also revealed that the angle of ripose and coefficient of static friction for stainless steel, glass, formica and plywood were 24.51o, 0.30, 0.34, 0.37 and 0.40 respectively. Stainless steel had the lowest coefficient of static friction and so will be most suitable among the materials tested for the production of okra seeds processing machines.