Abstract:Objective To analyze the motion, heat transfer, and mass transfer characteristics of sorghum in a vibrating fluidized bed and determine appropriate vibration and ventilation parameters to achieve efficient drying of sorghum.Methods Under the combined action of vibration and hot air, and based on the heat and mass transfer as well as the motion relationships between sorghum particles and the air medium during the fluidized bed drying process, a heat and mass transfer model was developed based on CFD-DEM fluid-solid coupling theory. The effects of vibration frequency, hot air temperature, and apparent wind speed on drying rate and drying unevenness were investigated.Results In the initial stage of drying, the unevenness of sorghum drying gradually increased due to the influence of particle motion and relative humidity. Particles in the lower bed layer experienced intense heat exchange because of strong airflow disturbance, with convection as the dominant heat transfer mode, whereas heat transfer in the middle and upper bed layers mainly occurred through conduction between particles. When the vibration frequency was 20 Hz, the minimum fluidization velocity decreased by 8.36%, and the bed expansion ratio decreased by 42.11%. When the vibration frequency was 21 Hz, the hot air temperature was 336 K, and the apparent wind speed was 1.7 m/s, the maximum drying rate of the vibrating fluidized bed reached 17.86%/h, and the minimum drying unevenness was 0.304. The validation experiment showed that the errors were all less than 5%.Conclusion Vibrating fluidized bed drying technology can achieve efficient and controllable drying of fresh sorghum.