Interaction of swing temperature and alternating airflow with vibration on drying uniformity in deep-bed wheat drying

Abstract

For fixed bed grain drying techniques, the biggest problem is the lack of drying uniformity. Deep-bed drying can be achieved in fixed bed after solving the problem of the drying uniformity, thereby reflecting the compact structure, simple operation and low running cost of the deep-bed drying equipment. A new fixed deep-bed drying method that features swing temperature and alternating airflow (STAA), coupled heating and tempering processes in time and space, and vibration induced grain circulation was investigated. The optimal tempering time is 0.67 times of the corresponding positive flow tempering time plus counter flow tempering time. The key to the vibration parameters is to make the wheat particles enter the global circulation roll mode under the joint excitation of airflow and vibration. The addition of vibration increased the average uniformity of positive and counter flow drying by 8.02%, and the average moisture content decreased by 1.28%. The introduction of vibration further enhances the drying uniformity and provides a new solution for continuing to increase the layer thickness.