EP0943867B1 - Ceramic lining for a combustor - Google Patents

Description

Technical field

The invention relates to a ceramic lining for thermally highly stressed Walls of combustion chambers according to the preamble of claim 1. Such Linings are used in particular as inner wall insulation for metallic combustion chambers, for example for gas turbines.

State of the art

A ceramic lining of a combustion chamber is known from DE 195 02 730 A1, which an uncooled removable lining of a combustion chamber with ceramic Elements that meet the high thermal and mechanical Stresses in a modern commercial, highly stressed gas turbine combustor Holds up.

The lining consists of at least one wall plate made of high temperature resistant Structural ceramics, also called monolithic ceramics, with at least a through opening and one fastener per Opening. The fastener is in one with the foot on the metallic Fastened wall-mounted metallic holding device, the Head of the fastener rests in the opening of the wall plate. The fastener also consists of high temperature resistant structural ceramics and is resiliently connected to the holding device. Between the metallic Wall and the ceramic wall plate is an insulation layer made of fiber ceramic intended. The advantages of this solution are that the lining is non-destructive and can therefore be used several times can. Furthermore, the elastic connection of the ceramic Structure to the metallic support structure between the thermal expansions metallic and ceramic components or deformations of the insulation layer be absorbed by mechanical stress.

These advantages are offset by the fact that the lining consists of many individual There are wall elements that must be attached separately that the Attaching the lining to the metallic support structure is quite complex, and that the lining is complicated due to the need for multiple layers is. In addition, it has been shown in practice that monolithic ceramics a shock or impact stress are very sensitive and often too Break go.

For this reason, fiber-reinforced ceramics should be used. So it was by K. Smith, A. Fahme: "Testing of Full Scale, Low Emissions, Ceramic Gas Turbine Combustor ", ASME, 97-Gas Turbine-157, Internatinal Gas Turbine & Aeroengine Congress & Exhibition, Orlando, Florida, June 2 - 3, 1997, a combustion chamber liner in the form of two concentrically arranged ceramic fibers Tubes presented. The outer tube has a diameter of approx. 0.75 m, while the inner tube has a diameter of approx. 0.35 m. Across from In monolithic ceramics, the fiber ceramic is also said to be essential have better resistance to temperature shock.

The disadvantage of this solution is that such tubes made of fiber ceramic for technical reasons so far only for relatively small dimensions can be produced. For the combustion chambers of modern high-performance However, gas turbines require an outside diameter of approx. 3.5 m. On Another disadvantage of the above The solution is that the ceramic tubes are replaced by external ones Convection must be cooled and a lot of cooling air is required for this.

Presentation of the invention

The invention tries to avoid all of these disadvantages. You have the task based on a ceramic lining made of fiber ceramics for combustion chambers develop which is suitable for large combustion chamber dimensions, the simple is to be attached to the metallic supporting wall and its heat transfer mainly done by radiation.

According to the invention, this becomes the case with a ceramic lining according to the preamble of claim 1 achieved in that the lining of individual juxtaposed segments in the form of hollow chambers with an inner wall facing the interior of the combustion chamber and one directly on the there is a metallic supporting wall on the outer wall.

The advantages of the invention are that there is no additional insulating material it is necessary that the ceramic fiber material is resistant to thermal shock and is fault tolerant and the lining consists of only a few individual parts.

It is expedient if the hollow chambers have a longitudinal expansion, which is adapted to the longitudinal extent of the combustion chamber. Of course the hollow chambers can also run transversely. The limitations in temperature resistance The fiber-ceramic materials can be removed maintained by guiding cooling air inside the hollow chambers be, so that the hollow chambers then in addition to their function as heat shields also perform the function of cooling air ducts.

In an embodiment variant, it is also advantageous if the hollow chambers are filled with insulating material on the inside. In this way, the temperature of the metallic supporting wall can be further dismantled.

Finally, the outer wall of each hollow chamber is advantageously made more resistant to high temperatures Screws and elastic elements, preferably disc springs fixed to the metallic supporting wall. This attachment is compared to that of monolithic ceramic components much easier. Because of the hollow chamber only needs to be fixed to the wall resting on the metal support the low thermal expansion of a wall thickness with the elastic elements be balanced.

Brief description of the drawing

In the drawing, an embodiment of the invention is based on a thermal shown highly loaded gas turbine combustion chamber.

Fig. 1

einen schematischen Längsschnitt der Brennkammer in einer ersten Ausführungsvariante;

Fig. 2

einen Querschnitt der Brennkammer entlang der Linie II-II in Fig. 1;

Fig. 3

eine perspektivische Teilansicht einer Brennkammer in einer zweiten Ausführungsvariante;

Fig. 4

eine perspektivische Teilansicht der Brennkammer in einer dritten Ausführungsvariante der Erfindung;

Fig. 5

einen Schnitt im Bereich der Befestigung der Auskleidung an der metallischen Tragwand.

Show it:

Fig. 1

a schematic longitudinal section of the combustion chamber in a first embodiment;

Fig. 2

a cross section of the combustion chamber along the line II-II in Fig. 1;

Fig. 3

a partial perspective view of a combustion chamber in a second embodiment;

Fig. 4

a partial perspective view of the combustion chamber in a third embodiment of the invention;

Fig. 5

a section in the area of fastening the lining to the metal support wall.

Only the elements essential for understanding the invention are shown. The system does not show, for example, the burners and the connection the combustion chamber to the turbine. The direction of flow of the media is with Arrows.

Way of carrying out the invention

The invention is explained below using exemplary embodiments and the figures 1 to 5 explained in more detail.

Fig. 1 shows a longitudinal section, Fig. 2 shows a cross section of the combustion chamber in schematic representation in a first embodiment of the invention. The Combustion chamber 1 consists of a metallic support wall 2, on the inside several segments in the form of hollow chambers 3 are arranged side by side. These hollow chambers 3 are made from fault-tolerant ceramic fiber material, which also has a very good thermal shock resistance. The inner wall 4 of each hollow chamber 3 is the interior of the combustion chamber 1 facing, while the outer wall 5 of each hollow chamber directly on the metallic Support wall 2 is applied. Between the individual in the circumferential direction juxtaposed hollow chambers 3 should only have the narrowest possible gap 6 (see FIG. 2) so that only a small convection flow occurs. Convection-free hollow chambers 3 are aimed at, so that the heat transfer from the hot combustion chamber to the (cooled) metallic support structure must mainly be done by radiation. The hollow chamber 3 thus forms even an insulating layer, it is not an additional insulating material, such as necessary when using linings with monolithic structural ceramics.

As can be seen from Fig. 1, the hollow chambers 3 extend over the entire Length of the combustion chamber 1, its longitudinal extent is the longitudinal extent adapted to the combustion chamber 1. The hollow chambers 3 are in the circumferential direction arranged side by side. Of course it is in another Embodiment also possible that the hollow chambers 3 transverse to the longitudinal direction run.

3 is a partial perspective view of a combustion chamber in a second Embodiment of the invention shown. In this variant are the hollow chambers 3 made of ceramic fiber material on the Metallic support wall 2 applied and serve on the one hand as a heat shield, on the other hand additionally flows through the interior of the hollow chambers 3 cooling air 7. This may be necessary if the material is exposed to extremely high temperatures for a long time is because the ceramic fiber material currently available with respect to Long-term stability at high temperatures does not meet all requirements enough. The solution to this problem is from different sides worked out. The hollow chambers arranged side by side in the circumferential direction 3 are in their longitudinal extent also the longitudinal extent of the Combustion chamber 1 adapted so that advantageously only a few individual parts for the lining are needed. In the entry area into the combustion chamber 1 are vertical to the above Hollow chambers also hollow chambers 3 made of ceramic fiber material arranged, which have an opening for the burner in the middle

Fig. 4 shows a third partial perspective view of a combustion chamber Embodiment variant of the invention. The ceramic fiber material Hollow chambers 3 are here directly with their outer wall 5 with the metallic support structure 2 connected, as exemplified with reference to FIG. 5 is explained. The inner wall 4 of the hollow chambers 3 is the interior of the Combustion chamber 1 facing. In contrast to the embodiment according to FIG. 3 4, the hollow chambers 3 are filled with insulating material 8. This too In this way, the temperature acting on the metallic support wall 2 is reduced. In this embodiment, it is also possible to the inner contour of the Modeling combustion chamber 1 solely using the fiber ceramic. In this way the metallic support structure 2 can be significantly simplified.

Fig. 5 shows an example of a possible type of attachment of the hollow chambers 3 on the metallic support wall 2. The attachment is relatively simple and without large spring elements possible because the thermal expansion takes place in the combustion chamber. The Hollow chamber 3 is on its outer wall lying on the metal support 2 5 fixed. This means that only the slight expansion of a wall thickness (approx. 5 mm) be intercepted. The attachment is done with high temperature resistant screws 9, for example made of fiber ceramics and with external elastic elements, z. B. disc springs.

LIST OF REFERENCE NUMBERS

1

combustion chamber

2

metallic bulkhead

3

hollow

4

inner wall of item 3

5

outer wall of item 3

6

gap

7

cooling air

8th

insulating material

9

screw

10

Belleville spring

Claims (5)

1. Ceramic lining for combustion chambers, which is fastened on the inner side of a metallic supporting wall (2) subjected to high thermal loading, the material of the lining being fibre ceramic, characterized in that the lining comprises individual segments arranged next to one another in the form of hollow chambers (3) with an inner wall (4), facing the interior of the combustion chamber, and an outer wall (5), resting directly on the metallic supporting wall (2).
2. Ceramic lining according to Claim 1, characterized in that the hollow chambers (3) have a longitudinal extent which is adapted to the longitudinal extent of the combustion chamber (1).
3. Ceramic lining according to Claims 1 and 2, characterized in that the hollow chambers (3) are provided for conducting cooling air (7).
4. Ceramic lining according to Claims 1 and 2, characterized in that the hollow chambers (3) are filled with insulating material (8).
5. Ceramic lining according to one of Claims 1 to 4, characterized in that the outer wall (5) of each hollow chamber (3) is fixed to the metallic supporting wall (2) by means of high-temperature-resistant screws (9) and elastic elements, preferably cup springs (10).

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