摘要
同轴探头法适合于测量果蔬等高损耗材料的介电特性,研究果蔬同轴介电特性与干燥含水率的相关性对于监测果蔬干燥加工过程中含水率的变化情况有重要理论指导意义。为此,以苹果为试验材料,利用同轴探头和网络分析仪测量了500~8.5GHz频率范围内苹果在微波干燥过程中的介电特性。研究表明:随着频率的增加,苹果试样介电常数呈下降趋势,介电损耗因子先下降后增加;通过介电特性指标与干燥含水率的拟合,建立了915MHz和2450MHz频率下苹果的相对介电常数、介质损耗因子与含水率的关系方程。研究结果可为利用同轴介电特性在线监测微波干燥含水率提供依据。
In order to study the relationship of the coaxial dielectric properties and microwave drying moisture content of apple,coaxial probe and network analyzers were used to measure the dielectric properties of apple in the frequency range of 500 MHz to 8.5 GHz.Mathematical models of the relationship between dielectric constant,dielectric loss factor and moisture content of apples were established.It was found that the dielectric constant of apples decreased with the increase of frequency from 500 MHz to 8.5 GHz,but the dielectric loss factor decreased at first with increasing frequency,and then increased with further increasing frequency.The results may provide references for the monitoring of moisture content in microwave drying.
作者
武新慧
郭玉明
孙静鑫
王璨
Wu Xinhui;Guo Yuming;Sun Jinxing;Wang Can(College of Engineering, Shanxi Agricultural University, Taigu 030801, China)
出处
《农机化研究》
北大核心
2018年第10期194-198,共5页
Journal of Agricultural Mechanization Research
基金
山西省研究生创新项目(2016BY072)
国家自然科学基金项目(31171450)
关键词
果蔬
介电特性
微波干燥
含水率
fruits and vegetables
dielectric properties
microwave drying
moisture content
