Optimization of operating conditions in the stage of steam turbine by black-box method

From the point of view of performance and economical in power plants, it is necessary to pay attention to the measurement of wet steam. The objective of this research is to employ the multi-objective black-box technique to minimize thermodynamic losses related to wet losses and improve the efficiency of the steam turbine, disregarding the process of film water deposition on the blade surface. For this purpose, a complete model of the steam turbine stage consisting of a stator-rotor is used to study wet steam. The simultaneous effects of two design variables on the performance of the steam turbine stage have been analyzed. The numerical model of wet steam flow has been used for calculating the values of the optimization criteria, including integral of wetness fraction (IWF), integral of mean droplet radius (IDR), turbine stage efficiency (TSE), condensation loss rate (Lr), and mass flow rate (Mr). According to the results, the temperature and pressure ratio were suggested to be 339.44 (K) and 0.51 (−), respectively, which improved the IWF by 30% and the IDR by about 7.3%. Also, the optimal mode increased TSE by about 1.3% and led to the reduction of Lr and Mr, by about 29%, and 1.3%, respectively.