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Secondary fuel nozzle with readily customizable pilot fuel flow rate

  • US 6,857,271 B2
  • Filed: 12/16/2002
  • Issued: 02/22/2005
  • Est. Priority Date: 12/16/2002
  • Status: Expired due to Term
First Claim
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1. A method of providing a secondary fuel distribution system having an annular premix nozzle and a separate premix pilot nozzle with a means to adjust and fine tune a fuel flow through said premix pilot nozzle, said method comprising the steps:

  • providing a housing for receiving fuel from a supply source and delivering fuel to a secondary fuel nozzle assembly which is attached to said housing, said secondary fuel nozzle assembly comprising;

    an elongated tube having opposing first and second ends and having a centerline defined therethrough;

    a nozzle tip region located proximate said elongated tube second end;

    a premix fuel nozzle comprising an annular tubular manifold circumferentially disposed around said elongated tube by a set of support members which are fixed to an extend radially outwards from said elongated tube, said manifold in fluid communication with said support members and having a plurality of first holes situated about its periphery facing in a downstream direction for dispersing fuel to a combustor, such that said fuel mixes with air passing around said manifold, wherein at least one of said first holes is offset circumferentially from said support member;

    a central core coaxial with said centerline and located radially within said elongated tube thereby forming a first passage between said central core and said elongated tube, said central core extending from proximate said elongated tube first opposing end to said second opposing end, said central core containing a second passage extending from proximate said elongated tube first opposing end to proximate said premix fuel nozzle for supplying fuel to said premix fuel nozzle, said central core also containing a third passage extending from downstream of said premix fuel nozzle to proximate said second opposing end each of said second and third passages are coaxial with said centerline, said central core further containing a plurality of air flow channels in fluid communication with said third passage and arranged in an annular array about said centerline, said air flow channels having an air flow inlet region and air flow exit region, and said first passage extending from proximate said first opposing end to upstream of said air flow inlet region of said air flow channels;

    means for transferring fuel from said first passage to said nozzle tip region;

    a premix pilot nozzle fixed to said central core at an axial position proximate said premix fuel nozzle such that said pilot nozzle is positioned within said third passage and coaxial with said centerline, said premix pilot nozzle having opposing first and second ends, an outer surface, and an internal passage, said pilot nozzle having a plurality of second holes proximate said pilot nozzle second end for dispersing fuel to said third passage, and a plate fixed to said first end of said premix pilot nozzle;

    determining a desired fuel flow rate for said premix pilot nozzle; and

    , placing at least one feed hole in said plate such that said internal passage is in fluid communication with said second passage and said at least one feed hole can be sized to match said desired fuel flow rate.

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