倒置微带贴片谐振器测量汽轮机湿度的研究

汽轮机蒸汽湿度的在线测量,对汽轮机的安全、经济运行具有重要的理论意义和实用价值。根据微扰法的基本理论,提出一种结构简单、灵敏度高的倒置微带贴片谐振器,实现汽轮机湿度的准确在线测量。湿蒸汽的湿度变化反应为谐振器介质层介电常数的变化,根据微带贴片谐振器的基本原理,仿真计算不同介电常数下的谐振频率,得到其变化关系曲线;讨论样本厚度、基质厚度和基质介电常数对频率偏移量的影响;设计微带贴片谐振器模型,并分别在HFSS和CST软件下进行仿真。研究及仿真结果表明,微带贴片谐振器模型适用于汽轮机蒸汽湿度的在线测量,蒸汽湿度每变化1%,谐振器频偏约为18 k Hz,约为微带缝隙谐振器频偏的3.6倍,有利于蒸汽湿度的准确测量。

Study on turbine wetness measurement by inverted microstrip patch resonator

The on-line measurement of turbine wetness has great theoretical significance and practical value to the safety and economic operation of steam turbine.According to the basic theory of perturbation method,a method is proposed to realize the turbine wetness measurement by inverted microstrip patch resonator,which has a simple construction with high sensitivity.The dielectric constant changes with the steam wetness change.The resonant frequencies of different dielectric constant are simulated based on the principle of microstrip patch resonator with the wet steam as sample substrate of resonator.The effects of sample thickness,substrate thickness and dielectric permittivity on the frequency offset are discussed.The microstrip patch resonator model is designed and simulated on the HFSS and CST.The study and simulation results show that the model is suitable for the on-line measurement of steam wetness of steam turbine.When the steam wetness changes 1％,the resonator frequency offset is about 18 kHz,which is about 3.6 times of frequency offset of microstrip slot resonator.The model is conducive to the accurate measurement of the steam wetness.