Patent Application
20120324897
The present disclosure relates generally to turbine systems and, more particularly, to a transition nozzle that may be used with a turbine system.
At least some known gas turbine systems include a combustor that is distinct and separate from a turbine. During operation, some such turbine systems may develop leakages between the combustor and the turbine that may impact the emissions capability (i.e., NOx) of the combustor and/or may decrease the performance and/or efficiency of the turbine system.
To reduce such leakages, at least some known turbine systems include a plurality of seals between the combustor and the turbine. Over time, however, operating at increased temperatures may weaken the seals between the combustor and turbine. Maintaining such seals may be tedious, time-consuming, and/or cost-inefficient.
Additionally or alternatively, to increase emissions capability, at least some known turbine systems increase an operating temperature of the combustor. For example, flame temperatures within some known combustors may be increased to temperatures in excess of about 3900° F. However, increased operating temperatures may adversely limit a useful life of the combustor and/or turbine system.
In one aspect, a method is provided for assembling a turbine assembly. The method includes integrally forming a transition nozzle including a transition portion and a nozzle portion. The transition nozzle includes at least one surface feature positioned to transfer heat away from the transition portion and/or the nozzle portion. The transition portion is oriented to channel combustion gases towards the nozzle portion.
In another aspect, a transition nozzle is provided for use with a turbine assembly. The transition nozzle includes a transition portion, a nozzle portion integrally formed with the transition portion, and at least one surface feature configured to transfer heat away from the transition portion and/or the nozzle portion. The transition portion is oriented to channel combustion gases towards the nozzle portion.
In yet another aspect, a turbine assembly is provided. The turbine assembly includes a fuel nozzle configured to mix fuel and air to create a fuel and air mixture, and a transition nozzle oriented to receive the fuel and air mixture from the fuel nozzle. The transition nozzle includes a transition portion, a nozzle portion integrally formed with the transition portion, and at least one surface feature configured to transfer heat away from the transition portion and/or the nozzle portion. The transition portion is oriented to channel the combustion gases towards the nozzle portion.
The features, functions, and advantages described herein may be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments, further details of which may be seen with reference to the following description and drawings.
The subject matter described herein relates generally to turbine assemblies and more particularly to a transition nozzle that may be used with a turbine assembly. In one embodiment, the transition nozzle is a unitary component including a liner portion, a transition portion, and a nozzle portion. In such an embodiment, the transition nozzle includes at least one surface feature configured to transfer heat away from the transition nozzle to facilitate cooling the liner, the turbine nozzle, and/or the transition piece. As such, the at least one surface feature enables the transition nozzle to withstand greater thermal loading, operate with increased operating temperatures, and operate with increased emissions capabilities.
As used herein, the terms “axial” and “axially” refer to directions and orientations extending substantially parallel to a longitudinal axis of a combustor. As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural elements or steps unless such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the present invention or the “exemplary embodiment” are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.
During operation, in the exemplary embodiment, ambient air is channeled through an air inlet (not shown) towards compressor 104. The ambient air is compressed by compressor 104 prior it to being directed towards combustor assembly 106. In the exemplary embodiment, compressed air is mixed with fuel, and the resulting fuel-air mixture is ignited within combustor assembly 106 to generate combustion gases that are directed towards turbine 108. Moreover, in the exemplary embodiment, turbine 108 extracts rotational energy from the combustion gases and rotates rotor shaft 110 to drive compressor 104. Furthermore, in the exemplary embodiment, turbine assembly 100 drives a load 112, such as a generator, coupled to rotor shaft 110. In the exemplary embodiment, load 112 is downstream of turbine assembly 100. Alternatively, load 112 may be upstream from turbine assembly 100.
In the exemplary embodiment, transition nozzle 200 includes in serial flow arrangement a combustion liner portion 202, a transition portion 204, and a turbine nozzle portion 206. In the exemplary embodiment, at least transition portion 204 and nozzle portion 206 are integrated into a single, or unitary, component. More particularly, in the exemplary embodiment, liner portion 202, transition portion 204, and nozzle portion 206 are integrated into a single, or unitary, component. For example, in one embodiment, transition nozzle 200 is cast and/or forged as a single piece.
In the exemplary embodiment, liner portion 202 defines a combustion chamber 208 therein. More specifically, in the exemplary embodiment, liner portion 202 is oriented to receive fuel and/or air at a plurality of different locations (not shown) spaced along an axial length of liner portion 202 to enable fuel flow to be locally controlled for each combustor (not shown) of combustor assembly 106. Thus, localized control of each combustor facilitates combustor assembly 106 to operate with a substantially uniform fuel-to-air ratio within combustion chamber 208. For example, in the exemplary embodiment, liner portion 202 receives a fuel and air mixture from at least one fuel nozzle 210 and receives fuel from a second stage fuel injector 212 that is downstream from fuel nozzle 210. In another embodiment, a plurality of individually-controllable nozzles are spaced along the axial length of liner portion 202. Alternatively, the fuel and air may be mixed within chamber 208.
In the exemplary embodiment, the fuel and air mixture is ignited within chamber 208 to generate hot combustion gases. In the exemplary embodiment, transition portion 204 is oriented to channel the hot combustion gases downstream towards nozzle portion 206 or, more particularly, towards a stage 1 nozzle. In one embodiment, transition portion 204 includes a throttled end (not shown) that is oriented to channel hot combustion gases at a desired angle towards a stage 1 turbine bucket (not shown). In such an embodiment, the throttled end functions as the stage 1 nozzle. Additionally or alternatively, transition portion 204 may include an extended shroud (not shown) that substantially circumscribes the stage 1 nozzle in an orientation that enables the extended shroud and the stage 1 nozzle to direct the hot combustion gases at a desired angle towards the stage 1 turbine bucket.
In the exemplary embodiment, transition nozzle 200 includes at least one surface feature 214 that is configured to transfer heat away from said transition nozzle 200. As such, surface feature 214 facilitates increasing a heat transfer coefficient of liner portion 202, transition portion 204, and/or nozzle portion 206. More specifically, in the exemplary embodiment, surface feature 214 provides additional surface area to interact with an air and/or fuel flow through transition nozzle 200. Moreover, in the exemplary embodiment, surface feature 214 imparts a flow disruption, or turbulence, to the air and/or fuel flow. As such, surface feature 214 facilitates cooling transition nozzle 200.
The size, shape, and/or orientation of surface feature 214 may vary, for example, according to an operating temperature of combustor assembly 106 and the amount of cooling that is needed, for example, to maintain a particular operating temperature. Surface feature 214 may be integrally formed with transition nozzle 200, coupled to a surface of transition nozzle, and/or machined into a surface of transition nozzle.
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During operation, in the exemplary embodiment, a fuel and air mixture is combusted within combustion chamber 208 to generate combustion gases that are subsequently channeled towards turbine nozzle 206. Air is channeled adjacent to surface feature 214 to facilitate cooling liner portion 202, transition portion 204, and/or nozzle portion 206. As described in more detail above, the unitary component includes at least one surface feature 214 configured to transfer heat away from the unitary component.
The embodiments described herein enable an interaction between the air and the surface features to be increased and, thus, a heat removal process of the transition nozzle to be enhanced. The integrated structure allows for a reduction in the number of parts required to complete the heat addition and flow throttling for the gas turbine design. A reduced part count also will reduce costs and outage time. The cooling enables the combustor to operate with increased operating temperatures and, thus, increased emissions capabilities.
The exemplary systems and methods are not limited to the specific embodiments described herein, but rather, components of each system and/or steps of each method may be utilized independently and separately from other components and/or method steps described herein. Each component and each method step may also be used in combination with other components and/or method steps.
This written description uses examples to disclose certain embodiments of the invention, including the best mode, and also to enable any person skilled in the art to practice those certain embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
