Method of manufacturing mixers

Abstract

A method for fabricating a unitary mixer is disclosed, said method comprising the steps of determining three-dimensional information of the unitary mixer having at least one swirler, converting the three-dimensional information into a plurality of slices that each define a cross-sectional layer of the unitary mixer, and successively forming each layer of the unitary mixer by fusing a metallic powder. Exemplary embodiments are disclosed, showing unitary mixer comprising an annular housing and a swirler having a unitary construction wherein unitary mixer is made by using a rapid manufacturing process. In one aspect of the invention, the rapid manufacturing process is a laser sintering process.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This Application claims priority to U.S. Provisional Application Ser. No. 61 / 044,116, filed Apr. 11, 2008, which is herein incorporated by reference in its entirety.BACKGROUND OF THE INVENTION[0002]This invention relates generally to combustors, and more specifically to mixers used for enhancing fuel / air mixing in gas turbine engine combustors.[0003]Modern day emphasis on minimizing the production and discharge of gases that contribute to smog and to other undesirable environmental conditions, particularly those gases that are emitted from gas turbine engines, have led to different combustor designs that have been developed in an effort to reduce the production and discharge of such undesirable combustion product components. Other factors that influence combustor design are the desires of users of gas turbine engines for efficient, low cost operation, which translates into a need for reduced fuel consumption while at the same time maintai...

AI Technical Summary

Problems solved by technology

For example, one way in which the problem of minimizing the emission of undesirable gas turbine engine combustion products has been attacked is the provision of staged combustion.

It will be appreciated that balancing the operation of the first and second stage burners to allow efficient thermal operation of the engine, while simultaneously minimizing the production of undesirable combustion products, is difficult to achieve.

In that regard, operating at low combustion temperatures to lower the emissions of NOx, can also result in incomplete or partially incomplete combustion, which can lead to the production of excessive amounts of HC and CO, in addition to producing lower power output and lower thermal efficiency.

Conventional combustor components such as, for example, mixers, are generally expensive to fabricate and / or repair because the conventional mixer designs include a complex assembly and joining of several components.

More specifically, the use of braze joints can increase the time needed to fabricate such mixers and can also complicate the fabrication process for any of several reasons, including: the need for an adequate region to allow for braze alloy placement; the need for minimizing unwanted braze alloy flow; the need for an acceptable inspection technique to verify braze quality; and, the necessity of having several braze alloys available in order to prevent the re-melting of previous braze joints.

Moreover, numerous braze joints may result in several braze runs, which may weaken the parent material of the component.

The presence of numerous braze joints can undesirably increase the weight and manufacturing cost of the mixer assemblies.

Complexities of the swirler geometries and the associated difficulties in the machining and normal wear of the tools such as the EDM electrodes during the machining process, cause significant manufacturing variability in the mixer assemblies.

Such manufacturing variability in the mixer assemblies may lead to undesirable aerodynamic flow variability in the mixers and adversely impact the aerodynamic performance of the combustor.

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