Abstract
In order to develop an ultra-sonic drying system for agricultural products, an ultra-sonic drying device with ultra-sonic generation plate, 19.5KHz, was designed and its performance was investigated. This paper focuses on the absorption characteristic of ultra-sonic wave into the layer of rough rice during drying period. Ultrasonic absorption properties of rough rice were measured at sound pressure level between 141.1 and 158.3dB, and layer thickness from 0 to 120mm. The sound pressure level decreases exponentially with traveling length and its energy was translated to heat energy in the rough rice layer.
