Numerical Simulation Of Dehumidifiction In Low Pressure Stage Of Steam Turbine

Wet steam generally arises in the low-pressure stage resulting from the low initial parameter among nuclear-powered steam turbine and geothermal steam turbine.And in general,the existence of wet steam adversely affects the stage which not only decreases the efficiency of the stage but also corrodes the rotor.Appropriate dehumidification structure will retard the issues caused by wet steam and improve the economy and security of the turbine to a great extent.Wet steam flow belongs to two-phase flow referring to complicated phase transition.Based on the non-equilibrium phase transition model,this research focuses on developing a numerical method applied to dehumidification structure in lowpressure stage.Numerical calculations are implemented for Moses nozzles and Dykas stator to testify the reliability of condensing flow model of wet steam.Results indicate that phase transition model adopted describes the steam flow phenomenon relevantly Besides,the nucleation sites and super-cooling degree can be predicted accurately.Numerical research is performed on wet-steam phase transition of prototype blade in flow channel.The distribution regularities are attained of section in 50% span and liquid parameters in the whole flow channel.Based on the study,the design of various dehumidification methods in stator flow channel and the analysis of humidification as well as demonstration are performed.Results indicate that the Surface Heating Dehumidification Method can decrease the droplets,the drop diameter as well as humidity.At the temperature of 300?,the dehumidification efficiency can reach 11.3%.The decrease of the humidity occurs with Trailing Edge Jet Dehumidification Method applied and the trailing edge flow field.At the slit width of 1.2mm,the the dehumidification efficiency can reach 10.4%.The Jet Dehumidification method on Suction Surface imact the nucleation sites to decrease the humidity of flow channel.At the jet orifice of 8 rows and 96 holes,the dehumidification efficiency can reach 35.4%.