Burner arrangement having a peripheral staging concept

Abstract

A burner arrangement has a plurality of mixing channels which extend parallel to the main axis of the burner arrangement and are arranged in at least two concentric circles, in which mixing channels fuel and discharge air from the compressor are mixed during the operation of the burner arrangement. The mixing channels are grouped together into fuel stages so as to produce an irregular staging in the peripheral direction of the burner arrangement.

Claims

1. A burner arrangement of a gas turbine combustor, comprising: a plurality of mixing channels, which extend parallel to a main axis of the burner arrangement and are arranged in at least two concentric circles, in the plurality of mixing channels fuel and discharge air from a compressor are mixed during operation of the burner arrangement, wherein the plurality of mixing channels are grouped together into fuel stages, wherein a fuel stage of the fuel stages comprises a portion of the plurality of mixing channels with a common fuel supply, which are controlled jointly during operation, and irregular staging in a circumferential direction of the burner arrangement is obtained in respect of a geometric distribution of the plurality of mixing channels associated with each of the fuel stages, wherein the fuel stage comprises different number of the plurality of mixing channels than in a different fuel stage of the fuel stages, wherein the common fuel supply in the fuel stage is different than a common fuel supply in the different fuel stage of the fuel stages, wherein the fuel stage comprises at least two subgroups, wherein each subgroup of the at least two subgroups comprises at least two directly adjacent mixing channels of the plurality of mixing channels in two different circles of the at least two concentric circles, wherein each subgroup of the at least two subgroups comprises different number of the plurality of mixing channels in each of the two different circles.

2. The burner arrangement as claimed in claim 1, further comprising: a centrally arranged pilot burner.

3. The burner arrangement as claimed in claim 1, wherein a first number of the plurality of mixing channels in a circle of the at least two concentric circles within one subgroup of the at least two subgroups is no more than twice a second number of the plurality of mixing channels in another circle of the at least two concentric circles of the one subgroup.

4. The burner arrangement as claimed in claim 1, wherein the subgroups in at least one of the fuel stages have different numbers of the plurality of mixing channels from each other.

5. The burner arrangement as claimed in claim 1, wherein a first number of the plurality of mixing channels in one of the fuel stages exceeds a second number of the plurality of mixing channels of another of the fuel stages different from the one of the fuel stages by no more than 50%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is explained in greater detail by way of example by means of the FIGURE.

DETAILED DESCRIPTION OF INVENTION

(2) The FIGURE, which is schematic and not to scale, shows a burner arrangement 1 having a plurality of mixing channels 4, which extend parallel to the main axis 2 of the burner arrangement 1 and are arranged in at least two concentric circles 3, in which mixing channels fuel and discharge air from the compressor are mixed during the operation of the burner arrangement 1. According to the invention, the mixing channels 4 are grouped in such a way into fuel stages 5, which are denoted by A and B in the FIGURE, that irregular staging is obtained in the peripheral direction 6 of the burner arrangement 1. The FIGURE shows just one example but the principle of fuel staging over the periphery can be applied to any desired number of mixing channels 4 and it is immaterial here whether there is an even or an odd number of mixing channels 4. The number of circles 3 in which the mixing channels 4 are arranged can also vary. In principle, the burner arrangement 1 can also have more than two premixed fuel stages 5 (A and B), but this is not worthwhile owing to cost considerations.

(3) The burner arrangement 1 includes a centrally arranged pilot burner 7 in order to stabilize the combustion of the fuel/air mixture supplied by the mixing channels 4.

(4) The illustrative embodiment in the FIGURE shows that the mixing channels 4 of the fuel stages 5, which are denoted by A and B, are distributed nonuniformly over the periphery. In this arrangement, at least two adjacent mixing channels 4 from the inner and the outer circle 3 always form a subgroup 8 of the respective fuel stage 5 (A or B). These two mixing channels 4 are supplemented by additional mixing channels 4 of the inner and/or outer circle 3, wherein the subgroups 8 do not contain significantly more mixing channels 4 from a circle 3.

(5) A fuel stage 5 can comprise two, three or more subgroups 8 with differing numbers of mixing channels 4, there being two subgroups 8 per fuel stage 5 in the example shown in the FIGURE.

(6) Furthermore, the FIGURE shows that not all the subgroups 8 have the same number of mixing channels 4, this being regarded as advantageous in respect of the irregularity to be achieved.

(7) Irregularities in respect of the arrangement and number of mixing channels are desired but should not be maximized. In particular, care should be taken to ensure that, as far as possible, the fuel stages 5 have the same number of mixing channels 4 in order to ensure stable combustion as regards flame loss.