微波同轴谐振腔测量液膜厚度的理论分析  

Theoretical Analysis of Microwave Coaxial Resonant Cavity Technique Measuring Thickness of Liquid Film

作　　者：钱江波[1] 严晓哲[1] 韩中合[1] 陈红健[1] 翟新杰 

机构地区：[1]电站设备状态监测与控制教育部重点实验室(华北电力大学),保定071003

出　　处：《汽轮机技术》2015年第2期89-92,共4页Turbine Technology

基　　金：国家自然科学基金资助项目(51016044);中央高校基本科研业务资助项目(13MS93)

摘　　要：汽轮机低压缸湿蒸汽区中,静叶片、动叶片及汽缸壁表面存在水膜的沉积、流动,在高速汽流拖拽撕裂下形成的较大水滴,会造成动叶片的严重水蚀,实时监测液膜厚度,对于叶片防护及机组的安全运行具有重要意义。采用开式微波同轴谐振腔作为液膜厚度测量传感器,根据谐振腔等效电路,建立了水膜厚度测量数学模型,推导了液膜厚度的测量关系式。设计了探针耦合同轴谐振腔传感器,仿真分析了谐振频率随水膜厚度的变化关系,确定了测量关系式中的待定系数,计算了不同温度条件下,液膜厚度随谐振频率的变化。Stator blade,rotor blade and cylinder wall of steam turbine low pressure cylinder exist deposit and flow of liquid film. The water film forms larger droplets with high speed steam flow drag,which could cause seriously water erosion of rotor blade. Real-time monitoring liquid film thickness is important to protect the rotor blade and has a significant guide meaning to the safe operation of steam turbine. The mathematical model of water film thickness measurement is established and the thickness measurement equation is deduced,based on equivalent circuit of resonant cavity. The relationship between water film thickness and resonance frequency is simulated,under different liquid film thickness conditions,and the undetermined coefficients of thickness measurement equation are determined. With different temperature conditions,the changing curve of liquid film thickness and resonance frequency is calculated. The thickness measurement equation of liquid film is in conformity with the changing relationship of liquid film thickness and resonance frequency acquired by the electromagnetic simulation.

关 键 词：微波测量 液膜厚度 同轴谐振腔 叶片去湿 汽轮机 

分 类 号：TK37[动力工程及工程热物理—热能工程]