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Opposed flow combustorRelated Patent Categories: Power Plants, Combustion Products Used As Motive Fluid, Process, Ignition Or Fuel Injection After StartingOpposed flow combustor description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070119179, Opposed flow combustor. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND [0001] The present invention relates generally to gas turbine devices and, in particular, to a system and method for providing opposed flows of fuel and air in a combustor. [0002] In traditional gas turbine devices, air is drawn from the environment, mixed with fuel and, subsequently, ignited to produce combustion gases, which may be used to drive a machine element or to generate power, for instance. Traditional gas turbine devices generally include three main systems: a compressor, a combustor and a turbine. The compressor pressurizes air and sends this air towards the combustor. The compressed air and a fuel are delivered to the combustor. The fuel and air delivered to the combustor are ignited, with the resulting combustion gases being employed to actuate a turbine or other mechanical device. When used to drive a turbine, the combustion gases flow across the turbine to drive a shaft that powers the compressor and produces output power for powering an electrical generator or for powering an aircraft, to name but few examples. [0003] Gas turbine engines are typically operated for extended periods of time, and exhaust emissions from the combustion gases are a concern. For example, during combustion, nitrogen combines with oxygen to produce oxides of nitrogen (NOx), and these NOx emissions are often subject to regulatory limits and are generally undesired. Traditionally, gas turbine devices reduce the amount of NOx emissions by decreasing the fuel-to-air ratio, and these devices are often referred to as lean devices. Lean devices reduce the combustion temperature within the combustion chamber and, in turn, reduce the amount of NOx emissions produced during combustion. [0004] Some regions of the United States require as little as three parts per million (ppm) N0x levels in natural gas operation. N0x emissions from a gas turbine have been significantly reduced using premixed combinations of natural gas. The degree of premixing has a strong impact on N0x reduction. However, highly premixed flames demonstrate increased instability and have proven difficult to anchor. Conventional premixed systems do not adequately reach N0x emission targets or theoretical limits so selective catalytic reduction (SCR) of N0x through ammonia injection has been employed. SCR is an expensive approach and improvements to the combustion system would reduce operating costs, such as the cost of electricity for operating the system. In systems powered by syngas or hydrogen, a diffusion flame has been used because high flame velocities associated with the hydrogen content may result in flashback into the premixer. Diluents are added at the injection tip to potentially reduce N0x emissions. [0005] In addition to natural gas, combustors may employ other fuels, such as syngas (synthetic gas) or hydrogen. Syngas poses challenges to flame stabilization and emission reduction at high firing temperatures. Premixed hydrogen combustion may result in a risk of flashback and typically produces significant N0x without premixing. Thus, there exists a need to provide an improved system and method to reduce the temperature of combustion in gas turbine systems to facilitate a reduction in NOx emissions from such systems. BRIEF DESCRIPTION [0006] Briefly, in accordance with one embodiment of the present invention, a combustor is provided. The combustor comprises a combustion chamber, a first inlet adapted to provide a first air flow to the combustion chamber in a first direction, a fuel controller adapted to provide a fuel flow to the combustion chamber in the first direction, an opposing inlet adapted to provide an opposing air flow to the combustion chamber in a second direction generally in opposition to the first direction and wherein the first air flow and the fuel flow interact with the opposing air flow to form a stagnation zone in the combustion chamber. [0007] A method of operating a combustion chamber in accordance with an exemplary embodiment of the present invention is also provided. The method comprises injecting a first air flow and a fuel flow into the combustion chamber in a first direction, and injecting an opposing air flow into the combustion chamber in opposition to the first air flow to form a stagnation zone in the combustion chamber. DRAWINGS [0008] These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: [0009] FIG. 1 is a diagrammatic representation of a gas turbine device, in accordance with an exemplary embodiment of the present invention; [0010] FIG. 2 is a partial and diagrammatic, cross-sectional view of a combustor assembly, in accordance with an exemplary embodiment of the present invention; [0011] FIG. 3 is a partial and diagrammatic, cross-sectional view of a combustor assembly, in accordance with another exemplary embodiment of the present invention; [0012] FIG. 4 is a partial and diagrammatic, cross-sectional view of a combustor assembly, in accordance with yet another exemplary embodiment of the present invention; [0013] FIG. 5 is a partial and diagrammatic, cross-sectional view of a combustor assembly, in accordance with still another exemplary embodiment of the present invention; and [0014] FIG. 6 is a flowchart illustrating an exemplary process for establishing an opposing flow in a combustor in accordance with an exemplary embodiment of the present invention. DETAILED DESCRIPTION [0015] As a preliminary matter, the definition of the term "or" for the purpose of the following discussion and the appended claims is intended to be an inclusive "or." That is, the term "or" is not intended to differentiate between two mutually exclusive alternatives. Rather, the term "or" when employed as a conjunction between two elements is defined as including one element by itself, the other element itself, and combinations and permutations of the elements. For example, a discussion or recitation employing the terminology "A" or "B" includes: "A", by itself "B" by itself and any combination thereof, such as "AB" and/or "BA." [0016] A flexible fuel combustor in accordance with an exemplary embodiment of the present invention is capable of burning hydrogen, natural gas or syngas in a gas turbine while maintaining low N0x emissions and low dynamics. Such systems may utilize opposed flows of fuel-air mixtures to create aerodynamic flame stabilization and to produce a highly stable flame zone in a combustor. Embodiments of the present invention may be compact in size and may provide low peak flame temperatures to help reduce undesirable N0x emissions. [0017] In an exemplary embodiment of the present invention, the combustor flame stabilization zone is removed from the burner. Reactants from the combustion process entrained the diluent rich products in the combustor before reacting. The flame is aerodynamically stabilized by an opposed flow of an ultra-lean fuel-air mixture, which creates a stagnation zone. The opposed flow also cools the combustor wall close to the stagnation zone. The combustion products flow toward the burner and then flow into the turbine hot section. [0018] Turning now to the drawings, FIG. 1 is a diagrammatic representation of a gas turbine device in accordance with an exemplary embodiment of the present invention. In FIG. 1, the gas turbine device is generally referred to by the reference numeral 10. The gas turbine device 10 comprises one or more compressor stages 12, a combustor 14 and one or more turbine stages 16. The compressor stages 12 provide a first air flow 20, which is adapted by the shape of a first air flow chamber 18 to flow into the combustor 14 via a first inlet 22. The combustor 14 also includes an opposing airflow chamber 24 to accommodate an opposing air flow 26. Moreover, the output of the compressor stages 12 is split to form the first air flow 20 and the opposing air flow 26. In the embodiment illustrated in FIG. 1, the opposing air flow 26 is delivered to the combustor 14 via an opposing inlet 28. [0019] A fuel source 30 provides fuel to a fuel controller 32. The fuel controller 32 delivers a first fuel flow 34 to the combustor 14 via the first inlet 22. The first airflow 20 and the first fuel flow 34 may be partially premixed. The first airflow 20 and the first fuel flow 34 are directed into the combustor 14 in a first direction, as indicated by the arrow 34 that represents the fuel flow. The opposing airflow 26 enters the combustor 14 in a second direction that is generally opposition to the first direction followed by the first airflow 20 and the first fuel flow 34. [0020] A perforated plate 36 may be disposed inside the combustor 14 between the first inlet 22 and the opposing inlet 28. The opposition between the first air flow 20 and the opposing air flow 26 creates a stagnation zone in the combustor 14. The stagnation zone, which may also be referred to as a reaction/combustion zone, is identified in FIG. 1 by the reference numeral 38. When combustion occurs, the combustion tends to happen near the stagnation zone 38. Continue reading about Opposed flow combustor... Full patent description for Opposed flow combustor Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Opposed flow combustor patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Opposed flow combustor or other areas of interest. ### Previous Patent Application: Method and device for compensating variations in fuel composition in a gas turbine system Next Patent Application: Methods and apparatuses for assembling a gas turbine engine Industry Class: Power plants ### FreshPatents.com Support Thank you for viewing the Opposed flow combustor patent info. 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