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The energy conversion process of steam within the turbine stages involves first converting the thermal energy of the steam into kinetic energy of the steam in its nozzle vanes, and then converting the kinetic energy of the steam into mechanical work output by the shaft in the rotor vanes. Steam at a certain temperature and pressure first expands and accelerates within the stationary nozzle channel; as a result, its pressure and temperature decrease while its velocity increases, with some of the thermal energy carried by the steam being converted into kinetic energy of the steam. The high-speed steam stream ejected from the nozzle cascade enters the moving cascade mounted on the impeller in a certain direction, where it continues to expand within the flow channels of the moving cascade. This causes a change in the direction and magnitude of the steam stream’s velocity, thereby exerting a force on the moving cascade and driving the impeller to rotate and perform work. The mechanical work is then transmitted outward through the turbine shaft, completing the conversion of kinetic energy into mechanical energy. As can be seen from the above, the energy conversion in a turbine occurs in two stages: the first stage is the conversion of the thermal energy carried by the steam into kinetic energy of the steam in the nozzle cascade and rotor cascade; the second stage is the conversion of the steam’s kinetic energy into mechanical work that drives the rotor to rotate, which is then transmitted outward through the turbine shaft.