Dragged by high speed steam flow

the water film at wet-steam region in steam turbine low pressure cylinder will form large droplets

causing serious water erosion of rotor blade. Real-time monitoring on liquid film thickness has great significance on rotor blade protection and unit safe operation. Thus

equivalent circuit of resonant cavity was built up. On this basis

the mathematical model of water film thickness measurement was established and the thickness measurement equation was deduced. The opening coaxial resonant cavity with good electromagnetic performance was designed. By using the HFSS software

the relationship between water film thickness and resonance frequency was analyzed

and the undetermined coefficients of thickness measurement equation were determined.Simulation on distilled water film whose dielectric constant is 81 shows that

when the water film thickness increases from 0 mm to 1 mm( with step of 0. 02)

the fitting similarity is 0. 995 and the mean square error is 0. 022. Therefore

this measurement formula has high reliability

which can be used to measure the liquid film thickness for static blades

cylinder walls

guide rings and other places.