Patent Application
20070157618
This invention relates generally to gas turbine engines, and more particularly, to combustor liner supports used in gas turbine engines.
At least some known combustors include at least one dome coupled to a combustor liner that defines a combustion zone. More specifically, the combustor liner includes an inner liner and an outer liner that extend from the dome to a turbine nozzle. Each liner is spaced radially inwardly from a combustor casing such that an inner and an outer cooling passageway are defined between each respective liner and the combustor casing. The inner passageway, in particular, enables cooling air to be channeled across an exterior of the inner liner. The cooling air facilitates reducing the temperature of the combustion chamber inner liner to facilitate reducing thermal stresses.
At least some known combustor inner liners are coupled to a forward inner nozzle support via a bolted joint. Such bolted joints, although structurally sound, may limit the useful life expectancy of the combustor liner. For example bolted joints may result in restricting cooling air flow through the inner passageway. As a result, high loss turns, recirculation zones, and/or cooling air backflow may be generated within the inner passageway, which may cause thermal stresses to be induced to the combustor inner liner. Over time, such stresses may decrease the life cycle fatigue (LCF) of the compressor. Moreover, bolted joints may also increase the overall weight of the combustor, which may adversely affect the performance and the life expectancy of the gas turbine engine as a whole.
In one aspect, a method for assembling a gas turbine engine is provided. The method includes providing a combustor liner support including a first portion formed with a plurality of circumferentially-spaced recessed areas, and a second portion extending from the first portion. The method also includes coupling the combustor liner support within a combustor such that during engine operations cooling air is channeled through the plurality of recessed areas to facilitate cooling the combustor liner support.
In another aspect, a combustor liner support for a gas turbine engine combustor is provided. The combustor liner support includes a first portion including a plurality of circumferentially-spaced recessed areas and a second portion extending from the first portion for coupling the combustor liner support to a portion of the combustor. The plurality of recessed areas are configured to channel cooling air through the combustor liner support.
In a further aspect, a gas turbine engine is provided. The gas turbine engine includes a nozzle assembly and a combustor assembly coupled upstream from the nozzle assembly. The combustor includes a liner and a liner support, wherein the combustor liner support includes a first portion and a second portion. The first portion includes a plurality of circumferentially-spaced recessed areas configured to channel cooling air through the combustor liner support. The second portion extends from the first portion.
A plurality of fuel igniters 62 extend through combustor casing 47 and outer passageway 52, and couple to combustor outer liner 40. Igniters 62 are bluff bodies that are placed circumferentially around combustor 16 and are downstream from the combustor domed end. Each igniter 62 is positioned to ignite a fuel/air mixture within combustion chamber 48, and each includes an igniter tube assembly 64 coupled to combustor outer liner 40. More specifically, each igniter tube assembly 64 is coupled within an opening 66 extending through combustor outer liner 40, such that each igniter tube assembly 64 is concentrically aligned with respect to each opening 66. Igniter tube assemblies 64 facilitate maintaining alignment of each respective igniter 62 relative to combustor 16.
To facilitate an adequate flow of cooling air 73 through passageway 54, combustor inner liner support 44 is fabricated with a plurality of passageways (described in more detail with respect to
Liner support second portion 72 is fabricated with a plurality of apertures 79 that are spaced circumferentially about an outer perimeter of second portion 72. More specifically, in the exemplary embodiment each aperture 79 is radially outward from a respective first portion coupling portion 77. Apertures 79 facilitate channeling cooling air 73, along flow path 74, and between combustor inner liner support second portion 72 and forward inner nozzle support 43. Specifically, apertures 79 facilitate directing air flow over fastener assemblies 45.
Forward inner nozzle support 43 is frusto-conical, and includes a plurality of attachment portions 80 spaced circumferentially about its perimeter. Each attachment portion 80 may be coupled to a corresponding combustor inner liner support coupling portion 77. Specifically, each coupling portion 77 and attachment portion 80 is coupled via fastener assemblies 45 to enable combustor inner liner support 44 to couple substantially flush against forward inner nozzle support 43. Accordingly combustor inner liner support 44 is radially outward from, and extends along an outer circumference of forward inner nozzle support 43.
In operation, air flows through low pressure compressor 12 from an upstream side 28 of engine 10. Compressed air is channeled from low pressure compressor 12 to high pressure compressor 14. Compressed air is then delivered to combustor assembly 16 wherein it is mixed with fuel and ignited. Combustion gases are channeled from combustor 16 to drive turbines 18 and 20.
Airflow exits high pressure compressor 14 at a relatively high velocity and is channeled into combustor 16 wherein the airflow is mixed with fuel and the fuel/air mixture is ignited for combustion using igniters 62. As airflow enters combustor 16, cooling air 73 is channeled through combustor inner passageway 54. Airflow in passageway 54 facilitates cooling inner liners 42.
Cooling air 73 is divided at combustor inner liner support 44. Specifically, a first portion of cooling air 73 is directed along outer flow path 74, and a second portion of cooling air 73 is directed along inner flow path 75. Flow path 74 directs cooling air 73 over fastener 45, and between inner liner 42 and combustor inner liner support second portion 72 to facilitate cooling inner liner 42. Furthermore, cooling air 73 flows along inner liner 42 and is channeled through apertures 79 to allow cooling air 73 to flow between combustor inner liner support second portion 72 and forward inner nozzle support 43.
To facilitate preventing air flow restriction in passageway 54, flow path 75 directs cooling air 73 between combustor inner liner support first portion 70 and forward inner nozzle support 43. Specifically, recessed areas 76 define passageways between adjacent pairs of coupling portions 77 and channel cooling air 73 between adjacent coupling portions 77 to facilitate cooling fastener assemblies 45. After passing through recessed areas 76, flow path 75 conjoins with flow path 74 between combustor inner liner support second portion 72 and forward inner nozzle support 43. As such, apertures 79 and recessed areas 76 facilitate providing uninhibited flow of cooling air 73 through inner passageway 54.
The above-described methods and apparatus facilitate allowing uninhibited air flow of cooling air through the combustor. Specifically air flow through the recessed areas defined in the combustor inner liner support facilitate preventing high loss turns, recirculation zones, and/or cooling air backflow within the inner passageway of the combustor. Accordingly, the recessed areas facilitate reducing thermal stresses on the combustor inner liner, and also facilitate increasing life cycle fatigue and improving the life span of the gas turbine engine.
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 said elements or steps, unless such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.
Although the methods and systems described herein are described in the context of fabricating a combustor inner liner support of a gas turbine engine, it is understood that the methods and systems described herein are not limited to combustor inner liner supports or gas turbine engines. Likewise, the combustor inner liner support components illustrated are not limited to the specific embodiments described herein, but rather, components of the combustor inner liner support can be utilized independently and separately from other components described herein.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
