汽轮机末级内湿蒸汽凝结流动计算与在线测量研究

Research on Calculation and Online Measurement of Wet Steam Condensation Flow in Last Stage of Steam Turbine

排汽湿度是影响汽轮机效率和安全运行的重要参数。基于国内外研究现状,采用微波谐振腔实现汽轮机排汽湿度的在线监测,随后结合实验数据通过数值模拟,得到汽轮机末级入口参数和出口参数变化对排汽湿度的影响。结果表明:对汽轮机末级后0.2 m处进行微波谐振腔湿度测量,在排除谐振腔振动与温度变化等因素干扰后,测得与光学法相近的结果;入口过冷度越大,湿度就越大,动叶出口平均湿度也越大;随着背压的升高,湿度会不断降低,动叶出口平均湿度同样降低。

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.