Thermal diffusivity is one of fundamental parameters to study and calculate heating, cooling, drying and moisture-absorbing processes of paddy grains. It governs the relationship between the ability of heat transfer and heat storage in heat transferring process, and is also an important parameter to measure the material's ability of temperature change when heated. Researches of thermal diffusivity of paddy grains in developed countries were commenced earlier than developing countries as well as China, and some methods of measurement were still in use. However, reports on study of measuring paddy grain's thermal diffusivity are very scarce. Most of values of thermal diffusivity reported in literatures were calculated from the values of thermal conductivity, specific heat and density. The objectives of this study are: 1) to determine thermal diffusivity of short paddy grains harvested in southern China using the theory of transient heat-transfer of cylinder; 2) to study the effect of moisture content on thermal diffusivity of paddy grains; 3) to develop a mathematical model to relate thermal diffusivity to moisture content.
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