Analysis of the Heat Transfer of Ginkgo Biloba Seeds during Radio-Frequency Heating

Abstract

AbstractFresh ginkgo biloba (GB) seeds are seasonal and susceptible to microbial spoilage, especially the growth of mold owing to GB seeds’ high-water content, which greatly limits their shelf life. As an efficient and special heating method, radio-frequency (RF) heating can be used to dehydrate ginkgo to preserve its nutritional value and reduce postharvest losses. However, the non-uniformity of RF heating restricts the development in industrialized application. In this study, the RF drying of GB seeds was performed to investigate the effect of RF heating on temperature. The distribution law of the entire temperature field was also observed. Using numerical simulation method, the coupling model of electromagnetic and heat transfer was established. The model was validated by the 6-min heating profile of GB seeds in a 12 kw and 27.12 MHz RF system. The model was also qualitatively validated by comparing the simulated temperature profiles on the three planes in the GB seeds with the corresponding thermal images. Quantitative validation was performed by comparing the simulated temperature of GB seeds on the three planes with experimental temperature acquired at places using thermocouples. Furthermore, the model can be effectively used to identify the distribution of electric fields in different positions and to achieve satisfactory heating uniformity.