Accelerator blades/vanes

Hot Corrosion. Hot corrosion is an accelerated form of oxidation that arises from the presence not only of an oxidizing gas, but also of a molten salt on the component surface. The molten salt interacts with the protective oxide so as to render the oxide nonprotective. Most commonly, hot corrosion is associated with the condensation of a thin molten film of sodium sulfate [7757-82-6], Na2S04, on superaHoys commonly used in components for gas turbines, particularly first-stage turbine blades and vanes. Other examples of hot corrosion have been identified in energy conversion systems, particularly coal gasifiers and direct coal combustors. In these cases the salt originates from alkali impurities in the coal which condense on the internal... 

Reaction turbine design also makes use of steam jets (which are produced by steam flowing across static vanes), although the turbine has rotor discs that incorporate movable blades rather than buckets. The design utilizes the reactive force produced by steam accelerating through a nozzle (created by the combination of a stationary vane and a moving blade) to rotate the shaft. 

At the time of design of the power plant, the failure mode disc detached at the hub was identified, together with the move backwards. The move was assumed to result in non-optimal gas flow over the fixed guide vanes and the rotating disc blades, such that the detached disc would safety slow down. Instead it continued to accelerate. 

Excessive moisture and particulates have an extremely negative impact on fan performance and cause two major problems abrasion or tip wear and plate-out. High concentrations of particulate matter in the inlet air act as abrasives that accelerate fan-rotor wear. In most cases, however, this wear is restricted to the high-velocity areas of the rotor, such as the vane or blade tips, but can afiect the entire assembly. 

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