Combustors, such as those used in industrial gas turbines, for example, mix compressed air with fuel and expel high temperature, high pressure gas downstream. The energy stored in the gas is then converted to work as the high temperature, high pressure gas expands in a turbine, for example, thereby turning a shaft to drive attached devices, such as an electric generator to generate electricity. For any given gas turbine, there may be several combustors, with each combustor housing multiple fuel nozzles.
The layout of a gas turbine mid-frame is typically obstructed by various components such as an inlet diffuser, transition mount, and various piping and components that may be distributed throughout the mid-frame. While the inlet diffuser provides a general diffusion of the air entering into the mid-frame, these structural obstructions lead to flow non-uniformity as the air enters the combustors. For example, the obstructions can cause the air to flow more readily to the upper portion of the headend while restricting airflow to the lower portion of the headend, providing more air to the combustors at the top of the turbine while less air is supplied to the combustors at the low portion. Further, while equal amounts of fuel are being supplied to each of the fuel nozzles, any unequal amounts of air supplied to each individual fuel nozzle shroud may create areas of richer air/fuel mixture potentially leading to burning within the nozzle shroud, for example. This may lead to overheated components and failure of the fuel shroud or injector, among other operational disruptions and damage to the system.
In one embodiment of the invention, a combustor of a gas turbine comprises one or more fuel nozzles arranged in a headend of the combustor, a combustion chamber in which mixture of air and fuel is combusted, an air path providing air flow to the combustion chamber, and a flow controller placed in the air path to regulate the amount of air provided to the one or more fuel nozzles.
In another embodiment of the invention, a flow controller in a combustor of a gas turbine comprises a body and a flow regulating portion configured to be placed in an air path providing air flow to a combustion chamber, the flow regulating portion including a plurality of holes configured to regulate the amount of air provided to one or more fuel nozzles in the combustor.
Various embodiments of a flow controller that provides equalized distribution of air entering into each fuel nozzle of a combustor are described. It is to be understood, however, that the following explanation is merely exemplary in describing the devices and methods of the present disclosure. Accordingly, any number of reasonable and foreseeable modifications, changes, and/or substitutions are contemplated without departing from the spirit and scope of the present disclosure.
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According to exemplary embodiments described below, a flow controller is provided to supply uniform amounts of air mass flow to each combustor 10. Further, exemplary embodiments described below also provide uniform amounts of air mass flow to each fuel nozzle 70 in a combustor 10.
While the above exemplary embodiments are described in relation to one fuel nozzle 70 in a combustor 10, in another exemplary embodiment, flow controller 100 may be placed around each fuel nozzle in a multi-nozzle combustor. Further, flow controller 100 may have different size, shape, and porosity to match the air flow need of each fuel nozzle 70.
In another exemplary embodiment, flow controller 100 as described above may be placed around the entire fuel nozzle assembly of a combustor 10 rather than around each fuel nozzle 70. Here, different sections of the flow controller 100 as described above may be formed with holes having differing size, shape, and/or porosity to adjust the air flow of the entire fuel nozzle assembly. In the alternative, flow controller 100 as described above may be placed at the entrance of the air path to the headend 50 to provide uniform air distribution of the compressed air to all of the nozzles 70 in the combustor 10. The foregoing exemplary embodiments may be combined to increase the efficiency as well as longevity of the combustion system without having to redesign or rearrange the internal structure of the combustion system.
Some of the advantages of the exemplary embodiments include: prevention of flashback and improved emissions by ensuring ideal air/fuel mixture through each fuel injector nozzle, reduced or eliminated flashback damage and ensure components meets service life target, and improved emissions will provide competitive market advantage.
It will also be appreciated that this disclosure is not limited to industrial gas turbines. For example, combustion systems in aero gas turbines and gas turbines in general can also realize advantages of the present disclosure. Further, the shapes, sizes, and thicknesses of the screen holes are not limited to those disclosed herein. For example, screen holes in the shape of a square, rectangle, triangle, and other polygonal structures, such as pentagon, hexagon, and octagon to name a few examples can also realize the advantages of the present disclosure. Additionally, the holes may be formed by various processes such as piercing, punching, or boring to form a perforated structure, or by die casting, for example.
The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. Moreover, the above advantages and features are provided in described embodiments, but shall not limit the application of the claims to processes and structures accomplishing any or all of the above advantages.
Additionally, the section headings herein are provided for consistency with the suggestions under 37 CFR 1.77 or otherwise to provide organizational cues. These headings shall not limit or characterize the invention(s) set out in any claims that may issue from this disclosure. Further, a description of a technology in the “Background” is not to be construed as an admission that technology is prior art to any invention(s) in this disclosure. Neither is the “Brief Summary” to be considered as a characterization of the invention(s) set forth in the claims found herein. Furthermore, any reference in this disclosure to “invention” in the singular should not be used to argue that there is only a single point of novelty claimed in this disclosure. Multiple inventions may be set forth according to the limitations of the multiple claims associated with this disclosure, and the claims accordingly define the invention(s), and their equivalents, that are protected thereby. In all instances, the scope of the claims shall be considered on their own merits in light of the specification, but should not be constrained by the headings set forth herein.
This application is related to co-pending U.S. patent application Ser. No. 15/410,109, entitled “FLOW CONDITIONER TO REDUCE COMBUSTION DYNAMICS IN A COMBUSTION SYSTEM,” filed Jan. 19, 2017, and co-pending U.S. patent application Ser. No. 15/414,063, entitled “RESONATOR FOR DAMPING ACOUSTIC FREQUENCIES IN THE COMBUSTION SYSTEM BY OPTIMIZING IMPINGEMENT HOLES AND SHELL VOLUME,” filed Jan. 24, 2017, which are incorporated herein by reference.