STUDY ON HEAT TRANSFER CHARACTERISTICS AND DRYING EXPERIMENT OF SINGLE SEED

Studies in the seeds drying field are presently aimed at macro heat and mass transfer of the whole seeds heap, but for drying of life materials, such as the seeds, the control of their internal temperature is essential. Therefore, the study of the heat transfer process of the internal single seed is pressed. This paper experimentally studied the measuring method of the thermal conductivity for the single broad bean seed, and then obtained an interrelated curve between the thermal conductivity and water contents for single seed. During the drying, the internal temperature could be derived from the surface temperature of the seeds and it contributed to deciding the safe drying temperature of the seeds. Then we derived the thermal conductivity of the seed coat and the cotyledon by testing and calculating the temperature fields of the inner cross section in the seed, which quantitatively indicated the difference of the thermal resistance between the seed coat and the cotyledon. In order to conquer the thermal resistance, appropriate drying conditions could increase the drying speed on the condition that the activity of seeds was maintained. In this paper, the Chinese cabbage seeds are selected to experimentally validate this method through the two-pass infrared radiation vibrated dryer and produces some satisfactory results. These results will contribute to the improvement of the drying quality and the efficiency of the life materials, such as the seeds.