Abstract: Exhaust steam wetness is an important parameter that affects the efficiency and safe operation of steam turbine. Based on the research status at home and abroad, the microwave resonator is used to realize the on-line monitoring of steam turbine exhaust wetness. Then, the influence of the inlet and outlet parameters of the final stage of the steam turbine on the exhaust steam wetness is obtained through numerical simulation combined with the experimental data. The results show that the wetness of the microwave resonator is measured at 0.2m after the final stage of the turbine, and the results are similar to those obtained by the optical method after the interference of the resonator vibration and temperature change is excluded. The higher the subcooling degree of the inlet, the higher the wetness, and the higher the average wetness of the outlet of the rotor blade. With the increase of back pressure, the wetness will continue to decrease, and the average wetness at the outlet of the moving blade will also decrease. The research results can provide reference for the efficient and safe operation of steam turbines.

Key words: steam turbine, wet steam, microwave resonator, wetness measurement, condensing flow