Design And Experimental Study On Infrared Corn Drying Test-bed

Infrared radiation drying was a complex process of non-steady-state heat and mass transfer, with the change of material moisture migration, textural features and quality characteristics. The depth study of drying characteristics and regularity of moisture migration were the foundation of the optimizing drying parameters, optimizing drying process and the design of drying equipment. Mechanization of grain drying was of great significance in agricultural equipment modernization. The infrared drying characteristics of corncob under the conditions of infrared radiation were researched. With the aim to solve the problems of high water content of corncob after harvest and seed damage caused by direct threshing, and reduce the losses of corn. And the specific content and results were as follows:⑴ Basing on the piecewise drying technology, the test-bed of infrared drying was designed. The delivery device, radiation device and other key parts were designed and analyzed.The shifter level could make the corncob, which entered the test stand, to roll and slide forward by handsetting. It could make sure the corncob absorb the radiant heat during the drying process, and improve the space utilization of equipment; the drop device was designed to make sure corncob could drop at the same time, which could avoid the corncob were jamming in the guide trough.⑵The infrared drying tests of corncob were done under different temperature conditions.The influence of constant temperature drying, variable temperature drying and other drying methods on moisture migration and the quality of drying were analyzed. The drying efficiency could be up to 2.25%/h when the isothermal drying temperature was about 58℃ and the radiation distance was about 190 mm, and the appearance quality could be best; the better variable temperature range was 55℃~65℃when the drying temperature was variable, and the drying quality could be better if the drying temperature was gradually improved.⑶The single-function test of corncob were done under multiple conditions. The influence of different drying temperature, power density, radiation distance and transportation speed on drying characteristics was studied. The better vibration frequency was about 0.48 W/cm2; The better drying temperature was about 58℃; The better radiation distance was about 190mm; The better transportation speed was about 700r/min when the range of transportation speed was700~1100r/min.⑷Basing on the above research, under the multiple conditions, the three factors and three levels orthogonal test were done and the parametersof infrared drying for corncob was optimized. The results showed that: the important order of the factors that affect the averagedrying rate of infrared radiation drying of corncob were B(radiation distance), C(power density), A(drying temperature) in turn; the average drying rate would be higher when the drying temperature was 61 ℃, radiation distance was 190 mm and the power density was0.48W/cm2; the drying effect would be better when the drying temperature was 58℃, the radiation distance was 190 mm and the power density was 0.48W/cm2.The self-made test-bed was with the characteristics of high heat transfer efficiency, low energy consumption, better drying uniformity, simple structure and reliable operation. It could reduce the damage rate of corn during corncob threshing and losses of corn. It was quite significant to make sure the bumper harvest of corn. It could lay a good foundation for the design of large infrared corncob dryer. It could provide a reference for the development of corn drying industry.