同一柱面电容传感器探头数学模型解析解

为快速、准确地检测谷物颗粒的含水率,设计了同一柱面电容传感器探头,采用电容器边缘效应感应周围物体的介电常数.利用电磁场相关理论,推导出传感器的电容量与被测颗粒物体相对介电常数的数学模型.设计了具体尺寸的传感器探头,计算出电容量与谷物相对介电常数的表达式.温度一定时,探头对稻谷进行了初步试验,发现装置的电容量与谷物的含水率呈线性关系.结果验证了同一柱面电容传感器探头的数学模型的正确性.

Analytical solution of mathematical model for the same cylindrical surface capacitive sensor probe

In order to detect moisture content of granular grain rapidly and accurately,a probe of the same cylindrical surface capacitive sensor is designed. The probe uses edge effect of capacitor to sense dielectric constant of the surrounding object.The mathematical expressions of the permittivity of the sensor and the relative permittivity of the particles are derived by using correlation theory of electromagnetic field.And the sensor probes of specific size are designed,and the expressions of the relative permittivity of grain and electric capacity are calculated.At a certain temperature,the probe conducts a preliminary test on rice and it is found that the capacitance of the device has a linear relationship with moisture content of grain. The results show that the mathematical model for the same cylinder surface capacitive sensor is correct.