Gas turbine with combined can-type and annular combustor and method of operating a gas turbine

Abstract

A gas turbine is provided which has a combustor comprising a plurality of can-type combustor elements and an annular element. Isolated combustion takes place in the can-type combustor thereby generating individual component hot gas streams. The component hot gas streams are merged in the annular part. Combustion oscillations are substantially avoided by decoupling combustion flames. Accordingly, temperature and pressure homogenization as well as combustion stabilization by cross-ignition is effected.

What is claimed is:  
     
         1 . A gas turbine, comprising: 
 a combustor for generating a stream of hot gas, said combustor comprising a plurality of can-type elements for accommodating combustion of air and fuel therein, and a single annular element for annularly orienting said plurality of can-type elements and merging said combustion such that combustion oscillations are substantially avoided.    
     
     
         2 . The gas turbine according to  claim 1 , further comprising a compressor for generating compressed air and means for directing said air to said can-type element.  
     
     
         3 . The gas turbine according to  claim 2 , wherein said merging of said combustion results in a stream of hot gas, and wherein said gas turbine further comprising a turbine for converting said stream of hot gas into mechanical energy.  
     
     
         4 . The gas turbine according to  claim 3 , wherein said turbine comprises an intake for receiving said stream of hot gas.  
     
     
         5 . The gas turbine according to  claim 3 , further comprising a shaft mechanically connecting said turbine, combustor and compressor.  
     
     
         6 . The gas turbine according to  claim 1 , wherein said can-type elements comprise a head having intakes for receiving fuel and air, an outlet exhausting said stream of gas, and a side wall connecting said head and outlet.  
     
     
         7 . The gas turbine according to  claim 6 , wherein said can-type element comprises a first area defining a combustion zone defined as a second area of a visible flame of said combustion.  
     
     
         8 . The gas turbine according to  claim 7 , wherein said first area substantially equals said second area.  
     
     
         9 . The gas turbine according to  claim 6 , wherein said annular element and can-type elements comprise an axial extension extending in the direction of flow of said stream of hot gas and wherein said annular element axial extension comprises at least half of the overall area of said can-type axial extensions.  
     
     
         10 . The gas turbine according to  claim 4 , wherein said intake of said turbine is partially formed by a vane support structure, said structure accommodating vanes thereon and located within said turbine, and said annular element is connected to and supported by said vane support structure.  
     
     
         11 . The gas turbine according to  claim 1 , wherein said can-type elements are supported by said annular element.  
     
     
         12 . The gas turbine according to  claim 11 , wherein said can-type elements are individually removable from said annular element.  
     
     
         13 . The gas turbine according to  claim 12 , wherein each said can-type elements are connected to said annular element by at least one connector facilitating removal of said can-type elements.  
     
     
         14 . The gas turbine according to  claim 6 , wherein said can-type elements are equally distributed along the circumference of said annular part and define hollow spaces between respective sidewalls of adjacent can-type elements.  
     
     
         15 . The gas turbine according to  claim 6 , wherein said annular element includes an outer shell, an inner shell located within said outer shell, ribs extending from said outer shell to said inner shell such that said can-type combustors are connected to said annular element side wall by at least one of said ribs.  
     
     
         16 . The gas turbine according to  claim 6 , wherein said sidewalls are diffuser-shaped.  
     
     
         17 . The gas turbine according to  claim 1 , wherein said can-type elements and annular element are arranged such that acoustic decoupling is substantially effected and combustion oscillations are substantially avoided.  
     
     
         18 . The gas turbine according to  claim 1 , wherein each of said can-type combustors includes a double wall, said double wall comprising an outer wall, an inner wall, and a hollow space defined by cooperating outer and inner walls, said hollow space conducting cooling fluid in between said outer wall and said inner wall.  
     
     
         19 . A Gas turbine, comprising: 
 a combustor for combustion of an air and fuel mixture in the production of a main hot gas stream, said combustor comprising a first and second region, said first region defining an area wherein individual combustion and production of component hot gas streams occurs, said first region having an area substantially defined by a visible flame of said combustion, and said second region defining an area wherein said component hot gas streams are combined to form said main hot gas stream before entering the turbine inlet, thereby generating a substantially homogeneous main gas stream temperature distribution; and    a turbine with a turbine inlet for receiving and conducting said main hot gas stream.    
     
     
         20 . The gas turbine according to  claim 19 , wherein the second region is substantially annular.  
     
     
         21 . The gas turbine according to  claim 20 , wherein said first region comprises a plurality of individual combustion regions substantially equally distributed about said second region.  
     
     
         22 . A method for reducing combustion oscillations in a gas turbine, comprising the steps: 
 conducting air and fuel into a plurality of distinct combustion zones,    incinerating said air and fuel in said distinct combustion zones,    generating individual hot gas streams in said zones thereby substantially avoiding acoustical coupling of flame instabilities occurring in said distinct combustion zones, and    merging said individual hot gas streams into a main hot gas stream, thereby substantially homogenizing said temperature distribution of merged individual hot gas streams.    
     
     
         23 . The method according to  claim 22 , further comprising the step of feeding said main hot gas stream through a turbine inlet.  
     
     
         24 . The method according to  claim 22 , wherein pressure of said main hot gas stream is substantially homogenized by said step of merging.