Thermal Properties of Soybean Pod as a Function of Moisture Content and Temperature

Abstract

In this study, specific heat, thermal conductivity, and thermal diffusivity of soybean pod were evaluated as a function of moisture content and temperature. Specific heat and thermal conductivity of soybean pod were measured by mixture method and transient state heat transfer apparatus respectively while thermal diffusivity was calculated using formula method. The experiments were done at four moisture levels [14.5, 21.5, 25.5, and 30.5 (w.b.%)] and four temperature levels [50, 150, 250, and 350°C] with 3 repetitions. Results showed significant variations in thermal properties values with changing moisture and temperature. Increasing moisture content and temperature increased specific heat and thermal conductivity from 1.856 to 4.39 kJ.kg-1°C-1 and 0.038 to 0.338 W.m-1°C-1 respectively. At all levels of temperature, thermal diffusivity decreased by increase in moisture content and at moisture increased by increase in temperature. The maximum amount of thermal diffusivity was obtained in the temperature and moisture content of 350 °C and 14.5 (w.b.%) ,respectively, which was equal to 2.62×10-7m2.S-1 and the minimum amount of thermal diffusivity was obtained in the temperature and moisture content of 50°C and 30.5% (w.b.%) ,respectively, which was equal to 7.18×10-8. Maximum thermal diffusivity coefficient in 350°C and 14.5% (w.b.) was 2.62×10-7m2.S-1 and minimum in 50 °C and 30.5% (w.b.) was 7.18×10-8m2.S-1.