Browse Prior Art Database

Sheet Metal Swirler

IP.com Disclosure Number: IPCOM000196780D
Published in the IP.com Journal: Volume 10 Issue 6B (2010-06-24)
Included in the Prior Art Database: 2010-Jun-24
Document File: 3 page(s) / 254K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

The swirler of a burner of gas turbines is normally built from machined solid elements, which are then assembled using bolts. Fuel conduits are drilled in the swirler vanes and different types of seals are used to prevent the fuel gas from escaping through clearances between the assembled parts. The current design comprises a large number of parts, is heavy, requires a lot of machining and is as a consequence cost-intensive. This proposed novel solution takes advantage of sheet metal pressing. The swirler vanes are formed from a flat sheet of metal using a press tool. If the height of the swirler vane is low compared to the overall dimensions of the swirler the wall along the full height of the swirler vane passage is made up of one sheet metal element. This may also be the case if a highly ductile material is used. On the other hand if the swirler passage is high and narrow or the swirler vane has two different shapes along its height two sheet metal pressings forming the vane passage are assembled facing each other. Preferably there will be an interlocking feature in the pressing of the surfaces in contact between the two swirler parts making up the height of the swirler vane passage. A further advantage of the two part design is that the fuel flow to each of the swirler parts can easily be controlled independently for improved turndown, fuel flexibility and combustion stability (see Figures 1-3).

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Sheet Metal Swirler

Idea: Ulf Nilsson, GB-Lincoln

The swirler of a burner of gas turbines is normally built from machined solid elements, which are then assembled using bolts. Fuel conduits are drilled in the swirler vanes and different types of seals are used to prevent the fuel gas from escaping through clearances between the assembled parts. The current design comprises a large number of parts, is heavy, requires a lot of machining and is as a consequence cost-intensive.

This proposed novel solution takes advantage of sheet metal pressing. The swirler vanes are formed from a flat sheet of metal using a press tool. If the height of the swirler vane is low compared to the overall dimensions of the swirler the wall along the full height of the swirler vane passage is made up of one sheet metal element. This may also be the case if a highly ductile material is used. On the other hand if the swirler passage is high and narrow or the swirler vane has two different shapes along its height two sheet metal pressings forming the vane passage are assembled facing each other. Preferably there will be an interlocking feature in the pressing of the surfaces in contact between the two swirler parts making up the height of the swirler vane passage. A further advantage of the two part design is that the fuel flow to each of the swirler parts can easily be controlled independently for improved turndown, fuel flexibility and combustion stability (see Figures 1-3).

Depending on the depth of the pressing the fuel supply ports may be drilled on the flat metal sheet before the pressing is carried out. Depending on the requirements of the shape of the hole the drilling may also be carried out after pressing operation. Due to that the wall of the swirler vane is comparatively thin it is easily accessible either from the inside of the swirler vane or from the swirler vane passage. A short drill can be used, similar to a dentist drill, or a laser drilling method. For example laser drilling from the outer radius of the swirler may be possible, making the fuel injection ports slightly upstream facing the oncoming airflow for potentially improved mixing performance. The repeatability and accuracy of the parts produced using pressing is high and will meet the tolerances required for effective area of the swirler and fuel air matching.

The shutdown time of the combustors is an important safety parameter. The more fuel that is present downstream of the shut off valve the longer it will take for the flame to extinguish. As long as the fuel is feed to the combustion chamber energy is added and the rotor keeps turning. In the novel solution the swirler vanes are now just a thin skin compared to solid blocks in the convention...