蒸気タービンのブレード劣化効果に関する数値解析

抄録

Thermal power plants using steam turbines are required to be high efficient. However, various parts including nozzle guide vanes and rotor blades degrade through long time operations. To keep the high efficiency of the power plant, appropriate maintenances have to be done as necessary. It is important to understand aerodynamic characteristics in deteriorated steam turbines in order to realize the appropriate maintenance. In the present study, the aerodynamics of the deteriorated steam turbine is examined numerically. The nozzle and the rotor blade profiles of the 1^st stage were obtained from a real steam turbine during the maintenance. The numerical boundary conditions were similar to the operation condition of the real thermal power plant. The numerical results show that the turbine power with the deteriorated blades is larger than that with the new blades because the mass flow of the main steam is larger. However, the turbine efficiency with the new blades is larger than that with the used blades.