基于同轴传输线电磁波检测油水介质介电常数的理论分析

Theoretical Analysis of Measuring Dielectric Constant of Oil-Water Mixture Based on Electromagnetic Wave on Coaxial Line

通过测量含水原油介电常数间接测量原油含水率是一种常用的方法。分析传输线上电磁波的传播特性,推导在混合波工作模式下传输线终端电磁波幅度和相位与介电常数的关系,通过数值模拟说明基于电磁波幅度特性检测介电常数方法的不可行性;基于电磁波相位特性检测介电常数的可行性。选择合适的传输线负载,即便在混合波模式下,也可以通过检测电磁波在传输线上的相移而获取传输线内流体介质的介电常数。

The general way of measuring the water holdup of oil-water mixture is to measure the dielectric constant of the mixture. Analyzed are the propagation characteristic of electromagnetic wave on coaxial line, derived is the relationship between the dielectric constant of the mixture in the coaxial line and the amplitude/phase of electromagnetic wave at the end of the coaxial line under hybrid wave mode, based on which related numerical simulations are performed. The researches show that the method based on the amplitude change of the electromagnetic wave isn t feasible for measuring dielectric constant, but it can be measured by the phase change if one reasonable load of the coaxial line be connected.