EFFECT OF MOISTURE CONTENT ON PHYSICO-THERMAL PROPERTIES OF PIGEONPEA

Abstract

ABSTRACT Physical and thermal properties of pigeonpea were measured as a function of moisture content. The average length, breadth and thickness increased linearly from 6.1 to 6.5 mm, 5.4 to 5.8 mm and 3.8 to 4.4 mm, respectively, with increase in moisture content from 10 to 30%. The sphericity increased from 0.82 to 0.84 and followed linear relationship. The kernel volume and surface area increased linearly from 52.6 to 70.4 mm3 and from 69.5 to 74.3 mm2, respectively, with increase in moisture content. The true density and bulk density decreased linearly from 1,299 to 1,203 kg/m3 and 830.3 to 762.9 kg/m3, respectively. However, no definite relationship was observed between porosity and moisture content in the range of 10 to 30%. The specific heat, thermal conductivity, and thermal diffusivity increased linearly from 1.85 to 2.31 kJ/kgC, from 0.123 to 0.171 W/mC and 8.13 × 16−8to 9.7 × 10−8 m2/s, respectively, with increase in moisture content. PRACTICAL APPLICATIONS The physical properties of agricultural materials are useful to design the processing equipment. The moisture content of agricultural materials greatly affects various physical properties. Therefore, the physical properties data at different moisture contents reported in this paper can be directly used to design/select processing equipment, like cleaners, graders, dryers, mills, conveyors, etc.