布拉格光纤光栅测量湿蒸汽两相流温/湿度的理论数学模型

Theoretic Mathematics Model Based on Fiber Bragg Grating Sensor Measurement in Two-phase Wet Steam Flow Temperature/Moisture

基于布拉格(Bragg)光纤光删(FBG)测量湿蒸汽两相流温度和湿度的物理模型,推导测量湿蒸汽两相流温度和湿度的数学模型,设计了新颖的测量结构和实验系统,并进行了分析。在同一光纤两段区域上写入不同中心反射波长的FBG,在一处FBG外面涂覆了湿敏材料(如PI材料),增强其感湿能力,把湿敏材料吸湿后发生湿膨胀引起的膨胀量当作产生湿应变来处理,同时还引入了湿敏材料与FBG的界面粘接系数,得出由于温度和湿度变化湿敏材料产生的应变使FBG波长发生漂移;把另一处FBG封装在温敏材料(如铝材料)中,只感受温度的响应,通过热应变对FBG作用,波长发生漂移,从而推导出测量的理论数学模型。

This paper presents theoretic mathematics model based on Fiber Bragg Grating （FBG） Sensor measurement in two-phase wet steam flow temperature/moisture according to its physical model, and designs a measuring system with special structure. The FBG are integrated into different position of the same fiber, moisture sensitive materials （PI materials） are smeared on one FBG in order to enhance sensitivity of FBG and moisture expansion after the moisture sensitive materials swelled is considered as moisture strain, furthermore, a coefficient of interface coherence between moisture sensitive materials and fiber is introduced, the strain of moisture sensitive materials makes the wavelength of FBG shift. The other FBG is encapsulated in the temperature sensitive materials （metal Aluminium）, and only responses temperature, the thermal strain makes the wavelength of FBG shift. Thus the theoretic mathematics model of measurement is deduced.