A Microwave Cavity Resonator Based System for Wetness Measurement in Steam Turbine

A microwave cavity resonator based system designed for on-line wetness measurement in steam turbine has been developed in this paper. A frequency-tracking unit inserted into the system allows the output frequency of the voltage-controlled oscillator (VCO) to follow the resonant frequency of the resonator filled by wet steam. Thus the output frequency of the VCO can be well related to the wetness level in the turbine. To study the performance of the system, it has been used to measure the permittivity of wet air generated by a self-made steam generator. A comparison of the experimental results and the theoretical value has shown good agreement between them, which demonstrates the feasibility of the system for wetness measurement in the turbine