Piloted flameholder construction

Claim 2

A piloted flameholder construction including a plurality of combustion zones, each zone having means for supplying fuel and air thereto for combustion, wherein the improvement comprises: supporting a plurality of flameholdErs rearwardly of at least the first combustion zone; and means for supplying hot combustion gases from at least one of the combustion zones to a point forwardly of each of the flameholders, each of these points being in substantially axial alignment with each of the flameholders, the combustion gases exiting from each of these points as a hot streak and being directed at and onto each of the flameholders.

Claim 3

A flameholder construction as in claim 1, wherein: the combustion zones include a pair of annular radially spaced walls each of the flameholders being supported from at least one of these pairs of walls, and the flameholders extend radially inwardly and outwardly from these walls.

Claim 4

A flameholder construction as in claim 2, wherein: the means for supplying hot combustion gases includes a plurality of transfer channels extending from at least one combustion zone to a point forwardly of the flameholders, each of the channels having an exit which is substantially axially aligned with a flameholder.

Claim 5

A piloted flameholder construction including a plurality of combustion zones, each zone having means for supplying fuel and air thereto for supporting combustion at each zone, wherein the improvement comprises: a first combustion zone including a first pair of radially spaced annular walls, the upstream ends of the spaced walls constituting the burner system inlet, this first combustion zone including a protected region bounded by a second pair of radially spaced annular walls inside the first pair of walls, means for permitting a predetermined amount of air to pass into this pilot combustion zone, the remainder of the airflow passing around the inlet of the burner system; a second combustion zone downstream of the first combustion zone including a third pair of radially spaced annular walls, the third pair of annular walls being radially spaced from the first pair of walls; a plurality of scoops positioned between the two pairs of annular walls, each of the scoops having exit locations directed either inwardly or outwardly, the inlets of the scoops facing forwardly to receive the air flowing past the first combustion zone; a plurality of transfer channels extending between the first combustion zone and the second combustion zone, the transfer chennels permitting passage of hot combustion gases from the first combustion zone to the exit of each of the transfer channels; and a third combustion zone downstream of the second combustion zone including a plurality of gutter-shaped flameholders, each of the flameholders being substantially in axial alignment and downstream thereof of the exits of each of the transfer channels, a hot gas streak issuing from the exit of each of the transfer channels and being directed at each of the flameholders.

Claim 6

A piloted flameholder construction including a plurality of combustion zones, each zone having means for supplying fuel and air thereto for supporting combustion at each zone, wherein the improvement comprises: a first combustion zone including a first pair of radially spaced annular walls, the upstream ends of the spaced walls constituting the burner system inlet, this first combustion zone including a protected region bounded by a second pair of radially spaced annular walls inside the first pair of walls, means for permitting a predetermined amount of air to pass into this pilot combustion zone, the remainder of the airflow passing around the inlet of the burner system; a second combustion zone downstream of the first combustion zone including a third pair of radially spaced annular walls, the third pair of annular walls being radially spaced from the first pair of walls; a plurality of scoops positioned between the two pairs of annular walls, each of the scoops having exit locations directed either inwardly or outwardly, the inlets of the scoops facing forwardly to receive the air flowing past the first combustion zone; a plurality of transfer channels extending between the first combustion zone and the second combustion zone, the transfer chennels permitting passage of hot combustion gases from the first combustion zone to the exit of each of the transfer channels; and a third combustion zone downstream of the second combustion zone including a plurality of gutter-shaped flameholders, each of the flameholders being substantially in axial alignment and downstream thereof of the exits of each of the transfer channels, a hot gas streak issuing from the exit of each of the transfer channels and being directed at each of the flameholders.

Claim 7

A flameholder construction as in claim 4 wherein: the third pair of walls support the flameholders, the walls being slotted at the point of support of each of the flameholders to permit passage of hot combustion gases from the second combustion zone along each of the flameholders.

Claim 8

A flameholder construction as in claim 5 wherein: a plurality of heat shields of substantially the same cross section as each of the flameholders is spaced axially therefrom and at the leading edge of each of the flameholders, the hot combustion gases from the second combustion zone being passed through the slots between each of the heat shields and flameholders and around the flameholders.

Claim 9

A flameholder construction as in claim 6 wherein: the heat shields and the flameholders are substantially U-shaped, and the apex of the U of the heat shield and flameholder is facing upsteam.

Claim 10

A flameholder construction as in claim 5 wherein: the flameholders supported from the inner annular wall extend radially inward therefrom and the flameholders supported from the outer annular wall extend radially outward therefrom.

Claim 11

A piloted flameholder construction for use with a ducted fan gas turbine engine, the flameholder being positioned in the relatively cool fan gas stream and including a plurality of combustion zones, each of the zones having means for supplying fuel and air thereto for supporting combustion in each zone, wherein the improvement comprises: an outer concentric wall including means for connecting the wall to the engine; an inner concentric wall spaced radially inward therefrom and also including means for connecting the wall to the engine, the two walls forming a duct therebetween within which the plurality of combustion zones are positioned, the combustion zones being arranged so that each successive downstream zone can accommodate a greater amount of flow than the zone immediately upstream; one of the combustion zones also including a pair of annular radially spaced walls, the flameholders being supported from both of the walls, the flameholders extending radially inwardly and outwardly from the wall thereby extending substantially across the entire duct; and means for supplying hot combustion gases from at least one of the combustion zones to a point forwardly of each of the flameholders, each of these points being in substantially axial alignment with each of the flameholders, the combustion gases exiting from each of these points as a hot streak and being directed at and onto the base of each of the flameholders.

Claim 12

A piloted flameholder construction for use with a ducted fan gas turbine engine, the flameholder being positioned in the relatively cool fan gas stream and including a plurality of combustion zones, each of the zones having means for supplying fuel and air thereto for supporting combustion in each zone, wherein the improvement comprises: an outer concentric wall including means for connecting the wall to the engine; an inner concentric wall spaced radially inward therefrom and also including means for connecting the wall to the engine, the two walls forming a duct therebetween within which the plurality of combustion zones are positioned, the combustion zones being arranged so that each successive downstream zone can accommodate a greater amount of flow than the zone immediately upstream; one of the combustion zones also including a pair of annular radially spaced walls, the flameholders being supported from both of the walls, the flameholders extending radially inwardly and outwardly from the wall thereby extending substantially across the entire duct; and means for supplying hot combustion gases from at least one of the combustion zones to a point forwardly of each of the flameholders, each of these points being in substantially axial alignment with each of the flameholders, the combustion gases exiting from each of these points as a hot streak and being directed at and onto the base of each of the flameholders.

Claim 13

A flameholder construction as in claim 9 wherein: there are three combustion zones and the flameholders are positioned downstream of the second combustion zone and the third combustion zone includes means for conducting hot combustion gases around each of the flameholders thereby heating each of the flameholders.

Claim 14

A piloted flameholder construction as in claim 10 wherein: each of the flameholders are gutter-shaped and a heat shield of substantially the same construction is positioned forwardly of each of the flameholders, each of the heat shields and flameholders thereby having a space therebetween, this space being in communication with one of the preceeding combustion zones thereby permitting a flow of hot combustion gases between the heat shields and the flameholders.

Claim 15

A piloted flameholder as in claim 11 wherein: the heat shields and the flameholders are substantially U-shaped, and the apex of the U of the heat shield and flameholder is facing upstream.

Claim 16

A piloted flameholder construction as in claim 10 wherein: the means for supplying the hot combustion gases includes a plurality of transfer channels each of the channels extending from the second combustion zone to a point forwardly of each of the flameholders.