# US 2008/0184708 A1 · Gas Turbine Combustor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0184708 A1 - Document ID: US20080184708A1 - Status: Published application - Kind: A1 - Application number: 11/574,203 - Filed: 2005-09-01 - Published: 2008-08-07 - Earliest claimed: 2004-09-10 - Assignees: Mitsubishi Heavy Industries, Ltd. - Inventors: Atsushi Moriwaki; Masataka Ohta; Keijiro Saitoh; Satoshi Tanimura; Shinji Akamatsu; Norihiko Nagai - Web page: https://patentgrep.com/patent/US20080184708A1 ## CPC - F23R 3/286: {having fuel-air premixing devices (F23R3/30 takes precedence)} - F23R 3/12: inducing a vortex - F23R 3/343: {Pilot flames, i.e. fuel nozzles or injectors using only a very small proportion of the total fuel to insure continuous combustion (ignition in gas-turbine plants F02C7/264; pilot flame igniters F23Q9/00)} - Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft - F23R: GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS (fluidised bed combustion apparatus specially adapted for operation at superatmospheric pressures F23C10/16) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A gas turbine combustor includes a pilot burner, a plurality of main burners disposed around the main burners on the radially outer side. Each of the main burners (2) includes an extension tube disposed at the downstream end. The outlet of the extension tube is shaped to have a radial edge which is parallel to the radial direction. In this manner, occurrence of flashback is effectively prevented. ## Claims ### Claim at position 1 1-18. (canceled) ### Claim 19 A gas turbine combustor comprising: a pilot burner; a plurality of main burners disposed around said pilot burner; and a basal plate for supporting said pilot burner and said main burners, wherein each of said main burners includes an extension tube provided at an downstream end thereof, wherein an outlet of said extension tube is formed so as to have two radial edges each of which is parallel to a radial direction, and circumferential edges connecting said radial edges, wherein said extension tubes are located downstream of said basal plate, wherein and said basal plate is provided with openings for allowing sweep air to flow therethrough toward downstream, and wherein an opening ratio of said openings in a region between every adjacent two of said extension tubes is larger than that of said openings in other regions. ### Claim 20 (depends on 19) The gas turbine combustor according to claim 19, wherein said outlet of said extension tube is shaped so that corner portions at which said radial edges are connected with said circumferential edges are rounded. ### Claim 21 (depends on 19) The gas turbine combustor according to claim 19, wherein an opening ratio of said openings in a region between every adjacent two of said extension tubes and inner than said extension tubes with respect to a radial direction is larger than an opening ratio in other regions. ### Claim 22 (depends on 19) The gas turbine combustor according to claim 19, wherein each of said main burners further includes: a main swirler for swirling premix gas and feeding the premix gas to said extension tube; wherein said openings are formed so that said sweep air is swirled in the same direction as a swirl direction of said premix gas. ### Claim 23 A gas turbine combustor comprising: a pilot burner; and a plurality of main burners disposed around said pilot burner, outside with respect to a radial direction, wherein each of said main burners includes an extension tube provided at an downstream end wherein an outlet of said extension tube is elongated so as to extend in a longitudinal direction, and wherein said longitudinal direction is oriented diagonally with respect to said radial direction. ### Claim 24 (depends on 23) A gas turbine combustor according to claim 23, wherein said outlet of said extension tube is shaped into an ellipse having a major axis parallel to said longitudinal direction, and wherein said major axis forms an angle other than 90 degrees with said radial direction. ### Claim 25 (depends on 19) The gas turbine combustor according to claim 19, wherein each of said main burners further includes: a burner outer liner which accommodates a nozzle for injecting fuel to air and a swirler for swirling premix gas containing said fuel and said air; and a plurality of spacers provided outside of said burner outer liner between said burner outer liner and said extension tube, and separated from each other, wherein said extension tube is inserted onto an downstream end of said burner outer liner so as to be located outside of said burner outer liner, and wherein said spacers are tapered down toward downstream. ### Claim 26 (depends on 19) The gas turbine combustor according to claim 19, wherein each of said main burners further includes: a burner outer liner which accommodates a nozzle for injecting fuel to air and a swirler for swirling premix gas containing said fuel and said air; and a spacer provided outside of said burner outer liner between said burner outer liner and said extension tube, wherein said extension tube is inserted onto an downstream end of said burner outer liner so as to be located outside of said burner outer liner, and wherein said spacer has an opening which is gradually enlarged toward downstream. ### Claim 27 (depends on 26) The gas turbine combustor according to claim 26, wherein said spacer is shaped into a ring, and connected to an outer side of said burner outer liner so as to surround said burner outer liner. ### Claim 28 (depends on 19) The gas turbine combustor according to claim 19, wherein each of said main burners further includes: a burner outer liner which accommodates a nozzle for injecting fuel to air and a swirler for swirling premix gas containing said fuel and said air; and a spacer provided outside of said burner outer liner between said burner outer liner and said extension tube, wherein said extension tube is inserted onto an downstream end of said burner outer liner so as to be located outside of said burner outer liner, and wherein said spacer is formed of a porous body. ### Claim 29 (depends on 28) The gas turbine combustor according to claim 28, wherein said spacer is shaped into a ring, and connected to an outer side of said burner outer liner so as to surround said burner outer liner. ### Claim 30 (depends on 19) The gas turbine combustor according to claim 19, wherein each of said main burners further includes: a burner outer liner which accommodates a nozzle for injecting fuel to air and a swirler for swirling flow containing said fuel and said air to generate premix gas, wherein said burner outer liner comprises: an outer liner body; and a front end portion which is provided at an downstream end of said outer liner body, and is smaller than said outer liner body in diameter wherein said extension tube is inserted onto said burner outer liner so as to contact against said outer liner body and to be opposed to said front end portion at a position downstream of said outer liner body, and has an opening at a position opposed to said front end portion. ### Claim 31 (depends on 30) The gas turbine combustor according to claim 30, wherein said opening is located so as to satisfy the following equation: L/g>2, which is represented by a radial width g of a gap between said front end portion and said extension tube and a distance L between an downstream end of said opening and an downstream end of said front end portion along said extension tube. ### Claim 32 (depends on 30) The gas turbine combustor according to claim 30, wherein said burner further includes a guide which is provided outside of said extension tube to guide air into said opening.