Theoretical Study of Water Film Thickness Measurements Based on an Improved Medium Perturbation Method

被引：0

作者：

Zhang S. ^{[1
]}

Zhang T. ^{[1
]}

Cao H. ^{[1
]}

机构：

[1] School of Electrical and Electronic Engineering, North China Electric Power University, Baoding

来源：

Zhang, Shu'e (zhangshue@ncepu.edu.cn) | 1600年 / Tianjin University卷 / 53期

关键词：

Alternating electric field; Dielectric; Electric field equation; Medium perturbation; Water film thickness;

D O I：

10.11784/tdxbz201901042

中图分类号：

学科分类号：

摘要：

Accurate determination of steam humidity is of great significance to the long-term stability and longevity of steam turbines.The measurement of steam humidity is affected by the water film thickness.Therefore, the issue of water film thickness needs to be investigated to produce a correct water film thickness measurement formula.The polarization process in the dielectric under alternating electric field was analyzed.The expression of the electric field in dielectric under alternating electric field was discussed.The electric field in the water film inside the cavity changes due to the alternating electric field.The approximation of the medium perturbation formula by a quasi-static method is no longer applicable.Based on the electric field equation in the dielectric of alternating electric field, the perturbation formula of the cavity was improved.A coaxial cavity and cylindrical cavity were designed by HFSS software.The variation of the electric field in the medium before and after perturbation at different frequencies and different media was obtained.Compared with the simulation data with the theoretical calculation data, the correctness of the electric field equation in the dielectric under the action of alternating electric field was proved.Based on the improved medium perturbation formula, the relationship model between the water film thickness and resonant frequency offset of the inner wall of the cylindrical cavity was established.The results were compared to the simulation data and media perturbation formula before and after theoretical data improvement.The results prove that under the same water film thickness, the resonant frequency obtained using the improved perturbation formula was more consistent with the actual simulation data, and the theoretical and simulation errors of the resonant frequency were improved by at least 35.7%. © 2020, Editorial Board of Journal of Tianjin University(Science and Technology). All right reserved.

引用

页码：272 / 278

页数：6

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