Suspension for an annular gas turbine combustor

The invention relates to a suspension of an annular gas turbine combustion chamber in the outlet region thereof on a housing wall, via an adjoining the outer combustion chamber wall, annular, kinked arm structure having an outer and an inner leg with respect to the gas turbine longitudinal axis. For example, reference is made to EP 0 564 172 A1 for the known state of the art.

Ring combustion chambers of gas turbines are usually carried in their front end by the projecting into the combustion chamber interior burner, while in the rear end, the so-called. Exit region, suitable on a housing wall, the so-called. <img file="EP0909924A2_D0001.tif" />combustion chamber outer casing ", are suspended. In particular, in the case of an effusion-cooled combustion chamber wall with a plurality of cooling air passage openings, the so-called. Effusionslöchern, care must be taken to ensure that the rear combustion chamber wall section undergoes sufficient cooling. The support structure for the suspension of the combustion chamber must therefore not hinder the effective cooling in this area. A suspension or a supporting structure which meets these requirements is shown, for example, in the abovementioned EP 0 564 172 A1. This annular, kinked arm structure, which has an inner and an outer leg relative to the longitudinal axis of the gas turbine, is also known in the art <img file="EP0909924A2_D0002.tif" />hair-pin "(hairpin) known. The inner leg closes with the outer leg at an acute angle, as is the inner leg relative to the combustion chamber wall inclined at an acute angle, resulting in a wedge-shaped annular gap between the inner leg and the combustion chamber wall, in the direction of flow of the outside of the outer combustion chamber wall along considered cooling air flow considered open. In this way, cooling air can optimally reach the rearmost end of the combustion chamber wall.

In the known state of the art, in which this bent arm structure or the so-called Hairpin / hair-pin is provided on the outer wall of the annular combustion chamber, this combustion chamber is based on this arm structure only on the housing wall surrounding the combustion chamber wall, whereas the actual attachment of the combustion chamber via the inner wall of the annular combustion chamber takes place. This can lead to undesirably large relative movements in the rear end portion of the combustion chamber.

To show a contrast improved combustion chamber suspension is the object of the present invention. The solution of this problem is characterized in that adjoins the outer leg (the arm structure), a flange which is connected via a releasable connecting element fixed to the (surrounding the combustion chamber wall) housing wall.

Advantageous embodiments and further developments are content of the dependent claims. Preferably, therefore, both legs on the circumference uniformly distributed arranged dovetailed openings, the narrowest portions of the bending line of the arm structure facing and open to the bending line, so that between each opening in the outer leg and the adjacent opening in the inner leg a so-called. There is a gap in the connection. This results in an advantageous suspension in the manner of a leaf spring.

The invention will be explained in more detail with reference to a preferred embodiment. It shows<dl id="dl0001" compact="compact"><dt>Fig. 1</dt><dd>a partial section through a gas turbine ring combustion chamber with a suspension according to the invention,</dd><dt>Fig. 2</dt><dd>the view X of FIG. 1 as a partial development of the annular arm structure, as well</dd><dt>Fig. 3</dt><dd>essential elements of the view A of FIG. 1.</dd></dl>

The reference numeral 1 denotes a ring combustion chamber of a gas turbine, which is designed here as a stepped combustion chamber and thus in addition to a plurality of annularly arranged pilot burners 2 frontally further also annularly arranged main burner 3 has. In the exit region 4 of the combustion chamber 1 - to this connects a plurality of vanes 5 supporting Leitschaufelring 6 - the combustion chamber 1 is suspended on a housing wall surrounding the entire combustion chamber structure 7. Provided for this purpose is an annular, bent formed arm structure 8, which adjoins the end portion of the outer combustion chamber wall 9a. Due to the kink along the also ring-shaped so-called. Crease line 10 has this arm structure 8 with respect to the gas turbine longitudinal axis 11 an inner leg 8a and an outer leg 8b, which meet in the crease line 10 and between them form an acute angle. Likewise, there is an acute angle between the outer combustion chamber wall 9a and the inner leg 8a and between the housing wall 7 and the outer trough 8b.

At the end of the outer leg 8b facing away from the crease line 10, a flange 8c extending in the radial direction adjoins, which is connected via a releasable connecting element 12 (in the form of a screw-nut connection) with a likewise radial direction, ie. H. perpendicular to the gas turbine longitudinal axis 11 extending flange 7a of the housing wall 7 is connected. After over the circumference of the combustion chamber 1 or the housing wall 7 distributed a plurality of such connecting elements 12 are provided, a secure and in particular undesirable relative movements preventing suspension of the combustion chamber 1 is ensured in the exit region 4.

Nevertheless, a certain mobility of the combustion chamber 1 relative to the housing wall 7 should be given. This flexibility is made possible by means of so-called. Bills 13 in the arm structure 8 or in the legs 8a, 8b. Are these breakthroughs or Openings 13 in at least one of the legs 8a, 8b, but preferably in both legs 8a, 8b suitably dimensioned and arranged, the arm structure 8 acts similar to a leaf spring with selectively shaped spring characteristic. Best results were achieved with the below explained design and arrangement of openings 13 in the arm structure 8.

As Fig. 2 shows, the Durchbrechnungen 13 are dovetail-shaped and distributed over the circumference of both legs 8a, 8b distributed uniformly, wherein the narrowest portions of the openings in each case the bending line 10 of the arm structure 8 faces. In addition, the Durchbrechnungen 13 are open to the bending line, so that - after these openings in the outer leg 8b and the inner leg 8a in the illustration of FIG. 1 quasi superimposed - between each Durchbrechnung 13 in the outer tavern 8b and the adjacent opening 13 in the inner leg 8a a so-called. Connection gap 14 is present. With this design, on the one hand results in a sufficient softness to accommodate expansions of the combustion chamber 1 relative to the housing wall 7, on the other hand, however, a sufficient strength to hang the combustion chamber 1 securely on the housing wall 7.

As Fig. 3 shows are shown in the stepped annular combustion chamber 1 shown here, the pilot burner 2 and the main burners 3 offset in the circumferential direction to each other. An optimal combustion chamber suspension according to the invention results in this arrangement when, in the cutting plane 15 of each burner (this cutting plane 15 extends as usual through the burner 2 or 3 itself as well as through the gas turbine longitudinal axis 11) at least in one of the legs 8a and 8b, but preferably in both of the legs 8a, 8b, an opening 13 is provided, wherein in this sectional plane 15 and the so-called. Connection gap 14 comes to rest.

However, it is also possible to arrange the apertures 13 offset relative to the burners 2 in the circumferential direction, so that then the cutting planes 15 of the individual burners 2, 3, for example, would come to lie exactly in the middle between two adjacent apertures 13 (not shown). However, any other intermediate positions of the apertures 13 in the legs 8a and / or 8b with respect to the burner sectional planes 15 are also possible.

In the embodiment shown here, with respect to each burner section plane 15 in the two legs 8a, 8b exactly one opening 13 is provided, ie a quotient of the number of openings 13 in one of the legs 8a and 8b (counted over the entire circumference) and the Total number of burners 2, 3 and gives exactly the value here <img file="EP0909924A2_D0003.tif" />1 ", or alternatively this quotient <img file="EP0909924A2_D0004.tif" /> (Number of breakthroughs) / (total number of burners) "but also accept other meaningful values, such as. 0.5 or 1.5 but also 2 or 2.5 or 3, the integer values ​​of this quotient having the advantage of simple periodic repetition. In other words, this means that alternatively only half as many openings 13 in the legs 8a, 8b of the arm structure 8 are provided as burners 2, 3 are present, or that three times as many openings 13 are present, as burners are provided. In particular, it should be noted that in non-tiered combustors other numerical values ​​for the mentioned quotient may be useful, as in the case of stepped combustors (as shown here).

With the described construction or Combustion chamber suspension is an optimal adaptation in terms of function, weight and life of the annular combustion chamber 1 possible. One reason for this is that periodic fuel injection through the burners 2, 3 provides periodic mechanical loading of the combustion chamber walls (the outer combustion chamber wall 9a and the inner combustion chamber wall 9b), which continues into the described suspension of the combustion chamber 1. With this construction described each stress peak can be opposed to the corresponding necessary structure. With the dividing ratios or quotients referred to in the last paragraph with regard to the number of perforations 13 relative to the number of burners, there is a fixed repetitive relationship between thermal / mechanical loading of the combustion chamber suspension in its entirety and each opening in the legs 8a, 8b due to the consequent mechanical state conditions.

As Fig. 1 shows, the inner combustion chamber wall 9b end a receptacle 16 for the adjoining the combustion chamber 1 vane ring 6, so that it is also held on the combustion chamber 1 and the advantageous suspension in an optimal manner. Furthermore, it can be seen between the end portion of the outer combustion chamber wall 9a, which adjoins the arm structure 8 of the invention, and the outer ring of the vane ring 6, a circumferential seal 17 which is held on a plurality of rivets 18 on the vane ring 6, but this and a Variety of other details in particular constructive nature quite differently designed by the embodiment shown, without departing from the content of the claims.

LIST OF REFERENCE NUMBERS

<dl id="dl0002" compact="compact"><dt>1</dt><dd>Annular combustor</dd><dt>2</dt><dd>Pilot burner</dd><dt>3</dt><dd>Main burner</dd><dt>4</dt><dd>exit area</dd><dt>5</dt><dd>vane</dd><dt>6</dt><dd>vane ring</dd><dt>7</dt><dd>housing wall</dd><dt>7a</dt><dd>flange</dd><dt>8th</dt><dd>arm structure</dd><dt>8a</dt><dd>inner thigh of 8</dd><dt>8b</dt><dd>outer thigh of 8</dd><dt>8c</dt><dd>flange</dd><dt>9a</dt><dd>outer combustion chamber wall</dd><dt>9b</dt><dd>inner combustion chamber wall</dd><dt>10</dt><dd>fold line</dd><dt>11</dt><dd>Gas turbine longitudinal axis</dd><dt>12</dt><dd>Connecting element: screw-nut connection</dd><dt>13</dt><dd>perforation</dd><dt>14</dt><dd>connecting gap</dd><dt>15</dt><dd>cutting plane</dd><dt>16</dt><dd>admission</dd><dt>17</dt><dd>poetry</dd><dt>18</dt><dd>rivet</dd></dl>