Measurement of thermal diffusivity of wheat and maize and comparison by Dickerson method

Thermal diffusion is occurred during heating and cooling of agricultural products. Cooling process involves the accumulation or loss of heat within a body which cause temperature distribution changes against time. Heat penetrates and releases into body or different porosity layers of agricultural products with special rate relevant to thermal diffusivity of samples. In this study, thermal diffusivity of wheat (variety: Sabalan, weight: 427/7 gr, MC: 9%db) and maize (variety: Crossing 704, weight: 362/1 gr, MC: 8/07%db) were measured and compared at four different levels of temperature (at). Thermal diffusivity increased with enhancing temperature of outer surface of cylinder. Minimum and maximum thermal diffusivity were obtained 1.268 103, 2.924 10-5, 0.862 10-3 and 3.135 10-5 for wheat and maize respectively. The results showed that thermal diffusivity alteration was much more for wheat than maize due to alteration of the temperature of outer surface.