Rotating assembly for a turbomachine

Abstract

A rotating assembly for a turbomachine includes a plurality of rotating members that extend radially outward from a central hub. Each of the plurality of rotating members includes a base portion detachably mounted to the central hub, a tip portion, a mid-span portion that extends between the base portion and the tip portion, and a shroud portion positioned at one of the tip portion and the mid-span portion. The shroud portion includes a pressure side and a suction side. At least one hard face interface member is secured to at least one of the suction side and the pressure side of the shroud portion. The at least one hard face interface member is both mechanically interlocked with, and metallurgically bonded to, the shroud portion.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to the art of turbomachines and, more particularly, to a rotating assembly for a turbomachine.[0002]Turbomachines employ a number of rotating components or assemblies. Turbines, for example, employ compressor stages and turbine stages that rotate at high speed when the turbine is in operation. In general, a stage includes a plurality of free-floating blades that extend radially outward from a central hub. Some blades include a shroud that limits vibration within a stage. The shroud is typically positioned at a tip portion of the blade, a mid portion of the blade or at both the mid portion and the tip portion of the blade. The shrouds are designed such that at high or operational speeds, the free-floating blades interlock to form an integral rotating member. At lower speeds, such as on turbine turning gear, the blades do not interlock and will often times impact one another. Impacts between the blades can cause damage tha...

AI Technical Summary

Benefits of technology

"The present invention relates to a rotating assembly for a turbomachine and a method of securing a hard face interface member to a shroud portion of a rotating member. The technical effects of the invention include improved performance and durability of the rotating assembly, as well as simplified manufacturing and maintenance processes. The rotating assembly includes a central hub and a plurality of rotating members that extend radially outward from the central hub. Each rotating member includes a base portion, a tip portion, and a mid-span portion. The shroud portion is positioned at the tip portion or the mid-span portion and includes a pressure side and a suction side. The hard face interface member is secured to the shroud portion with both a mechanical interlock and a metallurgical bond. The technical effects of the invention include improved performance and durability of the rotating assembly, as well as simplified manufacturing and maintenance processes."

Problems solved by technology

Impacts between the blades can cause damage that will shorten service life of the turbomachine.

Using a welding process to bond the hard face interface to the blade inherently produces a great deal of localized heat which, if not properly controlled, can weaken the impact resistance and other metallurgical properties at the interface of the materials being joined.

Excessive heat can also cause cracking in adjacent material during manufacture.

The z-notch radius portion is subjected to high stresses and therefore subject to cracking causing a release of material.

An additional failure mechanism can occur during high speed operation when tension and / or shear forces develop that over-stress the metallurgical bond.

Over time, the metallurgical bond can fail and the hard face coating is released from the blade becoming foreign object debris (FOD) in the turbomachine.

FOD flying around the turbomachine can damage the rotating components as well as inner surfaces of the turbine and lead to engine failure.

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