盐分对微波谐振腔测量蒸汽湿度的影响  

Influence of Salt Content on Steam Wetness Measurement by Microwave Cavity

作　　者：钱江波[1] 韩中合[1] 李恒凡[1] 张美凤[1] 

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

出　　处：《动力工程学报》2013年第7期523-529,共7页Journal of Chinese Society of Power Engineering

基　　金：国家自然科学基金资助项目(51076044);中央高校基本科研业务费资助项目(13MS93)

摘　　要：汽轮机排汽中含有盐分会改变湿蒸汽的介电性质,势必对湿度测量结果产生一定影响.将电导率引入纯净湿蒸汽复介电常数关系式和湿度测量关系式,定量分析了电导率对湿蒸汽介电性质及蒸汽湿度测量精度的影响.结果表明:湿蒸汽复介电常数的实部随微波波长增大、电导率提高、湿度增大、温度升高而变大;虚部随微波波长增大先增大后减小,随电导率提高、湿度增大、温度升高而变大;湿度测量偏差随电导率提高、湿度增大、温度下降、工作频率降低而增大;汽轮机排汽中的盐分对湿蒸汽复介电常数的影响很小,湿度测量可以达到较高的精度.The existence of salt content in turbine exhaust may change the dielectric properties of the wet steam, and may subsequently affect the wetness measurement results. The influence of electrical conductivity on both the dielectric properties of wet steam and the wetness measurement precision were quantitatively analyzed by introducing the electrical conductivity into the pure steam complex permittivity formula and the wetness measurement formula. Results show that the real part of the complex permittivity increa ses with rising microwave wavelength, conductivity, wetness and temperature, whereas the imaginary part first increases and then decreases with the rise of microwave wavelength, which increases with rising conductivity, wetness and temperature; the measurement deviation of steam wetness increases with rising con ductivity and wetness, and with reducing temperature and working frequency. The existance of salt content in turbine exhaust has little effect on the complex permittivity, when high precision may be achieved in the wetness measurement.

关 键 词：湿蒸汽 盐分 电导率 微波谐振腔 湿度测量 

分 类 号：TK261[动力工程及工程热物理—动力机械及工程]