A method of operating an axial turbine, having a stage including stationary blades and moving blades, each stationary blade having a radial height of an outlet thereof higher than the radial height of an inlet thereof, each moving blade being located downstream of a corresponding one of the stationary blades along a flow direction of a working fluid, the moving blades being constructed such that a moving blade front-end peripheral velocity Mach number exceeds 1.0, the method including restraining a radial velocity component of a working fluid flowing through an outer peripheral portion of the stationary blade from the stationary blade inlet to the stationary blade outlet, whereby the working fluid having passed through the stationary blade flows substantially parallel to the central axis of the turbine from the stationary blade outlet to the moving blade inlet.
1. A method of operating an axial turbine, the turbine comprising a stage including stationary blades and moving blades, each stationary blade having a radial height of an outlet thereof higher than a radial height of an inlet thereof, each moving blade being located downstream of a corresponding one of the stationary blades along a flow direction of a working fluid, each moving blade being constructed such that a moving blade front-end peripheral velocity Mach number exceeds 1.0, the method comprising a step of;
restraining a radial velocity component of a working fluid flowing through an outer peripheral portion of the stationary blade from the stationary blade inlet to the stationary blade outlet, whereby the working fluid having passed through the stationary blade flows substantially parallel to the central axis of the turbine from the stationary blade outlet to the moving blade inlet.