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This study proposed a mathematical model which was used to predict the temperature and moisture content of Ganoderma lucidum (Ganoderma boninense) during the radio frequency (RF) assisted heat pump (HP) drying process. The simultaneous heat and mass transfer equations were established based on the physical and flat plate models for drying Ganoderma lucidum and the specific assumptions for the proposed problem. The finite difference method was used to solve the proposed heat transfer and moisture transfer problem, in which, pdepe function was adjusted and complemented with Matlab software. The temperature and moisture content of the material in the drying process was predicted. The effect of the output RF power on the temperature and moisture content of the material was evaluated. The drying process's input parameters were drying air temperature of 40 o C, air velocity of 1.2 m/s, and an output RF power of 1.95 kW, 0.65 and 0 kW. The results showed that when the output RF power increases, the heating rate increases, and the drying time is shortened significantly. The drying material temperature reaches the drying air temperature in 20 minutes, 30 minutes, and 220 minutes and the drying time is 465, 555, and 700 minutes, corresponding to output RF power of 1.95 kW, 0.65 and 0 kW. The predicted temperature and moisture content of the material were compared with experimental drying data, and a considerably good agreement was found.

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In this study, computer simulations were conducted to assess the use of a circulating concurrent-flow dryer for rapeseed drying and to determined the effect of this drying method on the germination ratio of rapeseed after the drying process was complete. The simultaneous heat and mass transfer between air and rapeseed in a concurrent-flow dryer was examined by simulation. The drying simulation was based on several parameters with sequent time series. Equations concerning air psychrometrics, physical properties, thermal properties, equilibrium moisture content, thin layer drying of rapeseed, etc. were all combined to solve the simulation models. Based on energy and mass transfer in the concurrent-flow drying model, a simulation program for the circulating concurrent-flow rapeseed dryer was built along with a detailed description of the mathematical solution to the model.A pilot scale circulating concurrent-flow dryer(200 kg/batch) was used to verify the fitness of the simulation program. A comparison between the experimental data and the model predicted results was presented and discussed. The drying parameters and germination ratio were analyzed and the accuracy of the simulation program was evaluated. The simulation program proved to be reliable and was shown to be a convenient tool for predicting rapeseed drying and germination ratio of rapeseed in a concurrent-flow dryer.