Toroidal ring manifold for secondary fuel nozzle of a dln gas turbine

Abstract

A toroidal ring manifold for effectively dispersing premixing fuel with air in the secondary fuel nozzle of a combustor for a Dry Low NO x (DLN) gas turbine, thereby providing stable combustion with low nitrogen oxide (NO x ) emissions. The toroidal ring manifold is centered around a centerbody hub of a secondary fuel nozzle assembly in a premixing volume between the nozzle centerbody hub body and a centerbody cap. The ring manifold receives fuel from the nozzle body and dispenses premix fuel from a plurality of rows of individual holes on its downstream surface into an axial airstream. The number and location of the rows, the number, size and spacing of holes in each row, and the radial position of the toroidal ring manifold within the premixing volume are optimized to promote premixing.

1 . A toroidal ring manifold for dispensing fuel into a premixing zone of a secondary fuel nozzle for a Dry Low NO x  (DLN) gas turbine combustor, the toroidal ring manifold comprising:
 a toroidal ring manifold shell of a generally toroidal shape, including a central cavity within the shell;   a plurality of radial penetrations on an inner surface of the toroidal ring manifold shell, each penetration of the plurality of penetrations extending into the central cavity and being located in a predetermined arrangement on the inner surface;   a plurality of support arms extending inward radially from the inner surface of the toroidal ring manifold shell, one support arm of the plurality of support arms being attached to the toroidal ring manifold shell at each of the plurality of radial penetrations and extending inward radially from the inner surface of the toroidal ring manifold shell, wherein the support arm further includes an axial internal cavity for transporting fuel from an inner radial end to an outer radial end at the toroidal ring manifold shell; and   a plurality of penetrations through one poloidal surface of the toroidal ring manifold shell, the plurality of penetrations being located according to a predetermined arrangement.   
   
   
       2 . The toroidal ring manifold according to  claim 1 , each support arm of the plurality of support arms each comprising:
 a means at the inner radial end for attaching the support arm to a fuel source and a means at the outer radial end for attaching the support arm to the toroidal ring manifold, wherein the means may include a threaded connection.   
   
   
       3 . The toroidal ring manifold according to  claim 1 , wherein the predetermined arrangement for the plurality of penetrations through one poloidal surface of the toroidal ring manifold shell comprises:
 at least one row of holes, with a locus for centers of holes for each row being set at an individual predetermined angle with respect to a ring cross-section.   
   
   
       4 . The toroidal ring manifold according to  claim 3  wherein individual holes within each row of the at least one row of holes are evenly spaced circumferentially along the locus for the centers of the holes for each row. 
   
   
       5 . The toroidal ring manifold according to  claim 4 , wherein:
 individual holes within each row of the at least one row of holes are of the same diameter;   the holes within separate rows of the at least one row of holes may be at least one of a same diameter and a different diameter; and   a toroidal radius of the toroidal ring manifold shell is set to a predetermined size for positioning the at least one row of holes with respect to the poloidal axis.   
   
   
       6 . The toroidal ring manifold according to  claim 3 , wherein the predetermined arrangement for the plurality of penetrations through one poloidal surface of the toroidal ring manifold shell comprises:
 two rows of holes, with a locus for the centers of the holes for each row being set at an individual predetermined angle with respect to the ring cross-section.   
   
   
       7 . The toroidal ring manifold according to  claim 6 , wherein the two rows of holes, with a locus for the centers of the holes for each row being set at an individual predetermined angle with respect to the ring cross-section; comprises:
 a first row of holes, with a locus for the centers of the holes for the first row being set at a predetermined positive angle with respect to the ring cross-section; and   a second row of holes, with a locus for the centers of the holes for the row being set at a predetermined negative angle with respect to the ring cross-section.   
   
   
       8 . The toroidal ring manifold according to  claim 7 , wherein a diameter for the individual holes within first row of holes are smaller than a diameter for the individual holes within the second row of holes. 
   
   
       9 . The toroidal ring manifold according to  claim 7 , wherein centers for the individual holes within first row of holes are staggered circumferentially with respect to centers for the individual holes within the second row of holes. 
   
   
       10 . A secondary fuel nozzle assembly for a Dry Low NO x  (DLN) gas turbine combustor, the secondary fuel nozzle assembly comprising:
 a fuel supply at a rearward end of the secondary fuel nozzle assembly;   a nozzle body connected at the rearward end to the fuel supply;   a liner axially surrounding the nozzle body;   a toroidal ring manifold centered radially around the nozzle body for distributing fuel from the nozzle body into an axial airflow path around the nozzle body;   a premixing volume between the nozzle body and the liner;   a support structure for the toroidal ring manifold; and   a communication path for fuel from the nozzle body to the toroidal ring manifold.   
   
   
       11 . The secondary fuel nozzle assembly for a gas turbine combustor; the secondary fuel nozzle assembly further comprising:
 an internal fuel cavity within the nozzle body for delivering fuel from the fuel supply;   a plurality of radial passages from the internal fuel cavity arranged in a predetermined distribution around a circumference of the nozzle body;   a plurality of penetrations on an inner toroidal surface of the toroidal ring manifold, the plurality of radial penetrations being equal to the plurality of radial passages from the internal fuel cavity wherein the plurality of radial penetrations are arranged axially and circumferentially to align with the predetermined distribution of radial passages from the internal fuel cavity;   a plurality of radial support arms equal in number to the plurality of radial passages from the internal fuel cavity, each support arm including an internal passage between an inner radial end and an outer radial end, the inner radial end being attached to the nozzle body at the location of one of the plurality of radial passages from the internal fuel cavity and the outer radial end being attached to the toroidal ring manifold at the location of the penetrations of the inner toroidal surface; and   a predetermined arrangement for a plurality of penetrations through a downstream poloidal surface of the toroidal ring manifold shell including at least one row of holes, with a locus for centers of holes for each row being set at an individual predetermined angle with respect to a ring cross-section of the toroidal ring manifold.   
   
   
       12 . The secondary fuel nozzle assembly according to  claim 11 , wherein the predetermined arrangement for the plurality of penetrations through one poloidal surface of the toroidal ring manifold shell comprises:
 individual holes, within each row of the at least one row of holes, being evenly spaced circumferentially around the locus for centers.   
   
   
       13 . The secondary fuel nozzle assembly according to  claim 12 , wherein:
 individual holes within each row of the at least one row of holes are of the same diameter;   the individual holes within separate rows of the at least one row of holes may include at least one of a same diameter and a different diameter; and,   a toroidal radius of the toroidal ring manifold shell may include a predetermined size for positioning the at least one row of holes with respect to the poloidal axis.   
   
   
       14 . The secondary fuel nozzle assembly according to  claim 13 , wherein the predetermined arrangement for the plurality of penetrations through a downstream poloidal surface of the toroidal ring manifold shell comprises:
 two rows of holes, with a locus for the centers of the holes for each row being set at an individual predetermined angle with respect to the ring cross-section, including a first row of holes with a locus for the centers of the holes for the first row being set at a predetermined positive angle with respect to the ring cross-section and a second row of holes, with a locus for the centers of the holes for the row being set at a predetermined negative angle with respect to the ring cross-section.   
   
   
       15 . The secondary fuel nozzle assembly according to  claim 14 , wherein the diameter for the individual holes within first row of holes are larger than the diameter for the individual holes within the second row of holes. 
   
   
       16 . The secondary fuel nozzle assembly according to  claim 15 , wherein centers for the individual holes within first row of holes are staggered circumferentially with respect to centers for the individual holes within the second row of holes. 
   
   
       17 . A combustor for a Dry Low NO x  (DLN) gas turbine, the combustor comprising:
 a secondary fuel nozzle assembly including a premix fuel connection at the rearward end of the secondary fuel nozzle assembly; a nozzle body connected at a rearward end to the fuel connection; a toroidal ring manifold centered radially around the nozzle body for distributing fuel from the nozzle body into an axial airflow path around the nozzle body; a support structure for the toroidal ring manifold; and a communication path for fuel from the nozzle body to the toroidal ring manifold;   a liner circumferentially surrounding the secondary fuel nozzle assembly, including a penetration at the rearward end for admitting airflow to a premixing volume;   the premixing volume of a generally annular shape defined between the secondary fuel nozzle assembly and an inner wall of the liner; and   a swirler mounted at the forward end of the secondary fuel nozzle assembly.   
   
   
       18 . The combustor for a DLN gas turbine according to  claim 17 , the secondary fuel nozzle assembly further comprising:
 an internal fuel cavity within the nozzle body for delivering premix fuel from the fuel connection;   a plurality of radial passages from the internal fuel cavity arranged in a predetermined distribution around a circumference of the nozzle body,   a plurality of penetrations on an inner toroidal surface of the toroidal ring manifold, the plurality of radial penetrations being equal to the plurality of radial passages from the internal fuel cavity wherein the plurality of radial penetrations are arranged axially and circumferentially to align with the predetermined distribution of radial passages from the internal fuel cavity;   a plurality of radial support arms equal in number to the plurality of radial passages from the internal fuel cavity, each support arm including an internal passage between an inner radial end and an outer radial end, the inner radial end being attached to the nozzle body at the location of one of the plurality of radial passages from the internal fuel cavity and the outer radial end being attached to the toroidal ring manifold at the location of the penetrations of the inner toroidal surface;   a predetermined arrangement for a plurality of penetrations through a downstream poloidal surface of the toroidal ring manifold shell including at least one row of holes, with a locus for centers of holes for each row being set at an individual predetermined angle with respect to a ring cross-section of the toroidal ring manifold; and   a toroidal radius of the toroidal ring manifold shell being set to a predetermined value to align the at least one row of holes radially within the premixing volume between the secondary fuel nozzle assembly and the liner.   
   
   
       19 . The combustor for a DLN gas turbine according to  claim 18 , wherein the predetermined arrangement for the plurality of penetrations through a downstream poloidal surface of the toroidal ring manifold shell comprises:
 two rows of holes, with a locus for the centers of the holes for each row being set at an individual predetermined angle with respect to the ring cross-section, including a first row of holes with a locus for the centers of the holes for the first row being set at a predetermined positive angle with respect to the ring cross-section and a second row of holes, with a locus for the centers of the holes for the row being set at a predetermined negative angle with respect to the ring cross-section.   
   
   
       20 . The combustor for a DLN gas turbine according to  claim 19 , wherein the diameter for the individual holes within first row of holes are larger than the diameter for the individual holes within the second row of holes, and the centers for the individual holes within first row of holes are staggered circumferentially with respect to centers for the individual holes within the second row of holes.