Abstract: In order to clarify the effects of microwave drying parameters on moisture content and temperature of sorghum,the continuous drying test is carried out on the tunnel microwave dryer using the japonica sorghum “Longza 10” as raw material. The influence of magnetron tubes arrangement and microwave action distance on the sorghum drying uniformity of the experimental dryer is simulated and analyzed by HFSS software. The results show that with the increase of power per unit mass in the range of 2-6 W/g, the extent of moisture content is accelerated first and then gradually decelerates and the temperature of grain decreases. With the increase of drying time per cycle in the range of 1.02-5.0 min, the extent of moisture content is significantly increased and the grain temperature increased significantly. With the increase of air velocity in the range of 0.0-2.0 m/s, the extent of moisture content is decreased and the temperature of grain decreases slightly. The simulation analysis shows that the uniformity of electromagnetic field distribution is better when the magnetron tube of the dryer is arranged in “three two three arrangement way” and when the microwave action distance is 250 mm. It is shown theoretically that the tunnel microwave dryer used in this experiment is beneficial to the drying uniformity of sorghum. The research results will provide theoretical and data support for the industrial application of sorghum microwave drying.

Key words: microwave continuous drying, japonica sorghum, drying characteristics, drying uniformity

摘要： 为明确微波干燥条件对高粱含水率和籽粒温度等干燥特性的影响,以粳高粱“龙杂10”为原料,在隧道式微波干燥机上进行连续式干燥试验。并利用HFSS软件仿真分析试验用干燥机的磁控管排布方式和微波作用距离对高粱干燥均匀性的影响。结果表明:随着单位质量功率在2~6 W/g范围内逐渐增加,含水率下降幅度先加快后渐缓,籽粒温度有所下降;每循环干燥时间在1.02~5.0 min范围内逐渐增加,含水率下降幅度显著增强,籽粒温度增加显著;排湿风速在0.0~2.0 m/s范围增加,含水率下降幅度有减小趋势,籽粒温度略有下降。仿真分析表明干燥机磁控管采用“三二三排布方式”、微波作用距离为250 mm时电磁场分布的均匀性更好,从理论上表明本试验采用的隧道式微波干燥机对高粱干燥均匀性是有利的。研究结果将为高粱微波干燥产业化应用提供理论和数据支持。

关键词: 微波连续干燥, 粳高粱, 干燥特性, 干燥均匀性