Solid particle erosion resistant steam turbine nozzle

Abstract

The present invention is steam turbine nozzle resisting solid grain corrosion, relates to the improvement of nozzle structure for steam turbine, and aims at solving the problem of solid grain corrosion of steam turbine nozzle. The present invention has regulating stage blades fixed between inner nozzle ring and outer nozzle ring, nozzle passages formed with inner nozzle ring, outer nozzle ring and two adjacent regulating stage blades, and solid grain impact angle to the pressure surface of the regulating stage blades of 9-11 deg. The present invention has the solid grain impact angle to the pressure surface of the regulating stage blades greatly decreased from available technology, so as to avoid the high erosion area of the blade material and decrease the number of solid grains nozzle exit surface obviously. The present invention has less stage efficiency degradation each month and longer nozzle service life compared with available technology.

Description

Technical field:

[0001] The invention relates to an improvement of the nozzle structure of a steam turbine. Background technique:

[0002] Solid particle corrosion (Solid Particle Erosion) is one of the main reasons for the reduction of flow efficiency of supercritical thermal power steam turbine units. Due to the high temperature and high pressure characteristics of supercritical units, the corrosion of solid particles in steam turbine nozzles is common. Solid particles are iron oxide particles formed by ferrite alloys on the inner surface of boilers, heaters or steam pipes under the action of high temperature and high pressure steam. This kind of brittle oxide is formed at a certain point on the inner surface of the boiler, heater or steam pipe. After accumulating to a certain extent, it will peel off due to the instantaneous temperature change during the start-up and stop of the unit or the load change process, forming countless sharp corners. Hard particles, which pass...

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