Thermal Conductivity, Specific Heat, and Thermal Diffusivity of Saponaria vaccaria Seed Particles

Abstract

The seeds of Saponaria vaccaria (prairie carnation) are the major source of saponins, which are used for the treatment of cancers and various infections. The thermal conductivity, specific heat, and thermal diffusivity of Saponaria vaccaria seed particles were determined at temperatures ranging from 25°C to 55°C, moisture content from 15.35% to 80% dry basis, and effective density from 516.5 to 1328.05 kg m-3. The thermal conductivity was measured by the transient technique using a line heat source for the particles with and without air, and pores filled with ethanol-water solutions of 10%, 40%, 70%, and 100% volumetric ethanol concentrations. The values ranged from 0.057 to 0.625 W m-1 °C-1. Specific heat was measured by differential scanning calorimetry and ranged from 1118.57 to 3023.78 J kg-1 °C-1. Thermal diffusivity was calculated from thermal conductivity, specific heat, and density and ranged from 0.60 × 10-7 to 1.58 × 10-7 m2 s-1. Particle and bulk densities of the particles followed a parabolic relationship with moisture content. Thermal conductivity increased with moisture content. Specific heat increased linearly with temperature and exhibited ascending-descending trends with moisture content. Thermal diffusivity followed descending-ascending trends with moisture content. Regression models for all the properties were developed based on the experimental data.