EP1528343A1 - Refractory tile with reinforcing members embedded therein, as liner for gas turbine combustion chamber - Google Patents

Abstract

Heat shield element (26), especially for the inner lining of a combustion chamber of a gas turbine, comprises a base body (28) made of a strengthened cast ceramic material containing a number of reinforcing elements (30). Independent claims are also included for: (1) Combustion chamber with an inner lining comprising heat shield elements; and (2) Gas turbine comprising the above combustion chamber. Preferred Features: Each reinforcing element is made of a ceramic composite material.

Description

The invention relates to a heat shield element, in particular for the inner lining of a combustion chamber or a Oven. The invention further relates to a combustion chamber with an inner lining formed of heat shield elements and a gas turbine with a combustion chamber.

A thermally and / or thermomechanically highly loaded Combustion chamber, such as a kiln, a hot gas channel or a combustion chamber in a gas turbine in which a hot Medium is generated and / or out, is for protection against high thermal stress with a corresponding lining Mistake. The lining is usually made heat-resistant material and protects a wall of the combustion chamber before direct contact with the hot medium and the associated strong thermal load.

US Pat. No. 4,840,131 relates to an attachment of ceramic lining elements on a wall of a furnace. Here is a rail system which is attached to the wall is. The lining elements have a rectangular shape with a planar surface and consist of a heat insulating, refractory, ceramic fiber material.

U.S. Patent 4,835,831 also deals with application a refractory lining from a wall of a Furnace, in particular a vertically arranged wall. On the metallic wall of the furnace becomes one of glass, ceramic, or mineral fibers existing layer applied. These Layer is attached by metallic clips or by adhesive attached to the wall. On this layer is a wire mesh with applied honeycomb meshes. The mesh is used also securing the layer of ceramic fibers against a fall down. In addition, it is fastened by means of a bolt a uniform closed surface of refractory Material applied. With the described method is largely avoided that impinging during spraying refractory particles are thrown back as this with a direct spraying of the refractory particles the metallic wall would be the case.

A ceramic lining of the walls of thermally highly stressed combustion chambers, for example of gas turbine combustion chambers, is described in EP 0 724 116 A2. The lining consists of wall elements made of high temperature resistant structural ceramic, such. As silicon carbide (SiC) or silicon nitrite (Si ₃ N ₄ ). The wall elements are mechanically fixed by means of a central fastening bolt to a metallic support structure (wall) of the combustion chamber. Between the wall element and the wall of the combustion chamber, a thick thermal insulation layer is provided, so that the wall element is spaced correspondingly from the wall of the combustion chamber. About three times as thick in relation to the wall element insulation layer consists of ceramic fiber material, which is prefabricated in blocks. The dimensions and the external shape of the wall elements are adaptable to the geometry of the space to be lined.

Another type of lining of a thermally highly loaded Combustion chamber is specified in EP 0 419 787 B1. The lining consists of heat shield elements that mechanically a metallic wall of the combustion chamber are supported. The heat shield elements touch the metallic wall directly. To avoid overheating the wall, z. B. as a result of direct heat transfer from the heat shield element or by penetration of hot medium in the through formed the adjacent heat shield elements Column, is that of the wall of the combustion chamber and the heat shield element formed space with cooling or sealing air acted upon. The blocking air prevents the penetration of hot Medium up to the wall and at the same time cool the wall and the heat shield element.

WO 99/47874 relates to a wall segment for a combustion chamber and a combustion chamber of a gas turbine. This is a Wall segment for a combustion chamber, which with a hot Fluid, e.g. As a hot gas, can be acted upon, with a metallic Support structure and one on the metallic support structure attached heat shield element specified. Between the metallic support structure and the heat shield element is a deformable separating layer inserted, the possible relative movements receive the heat shield element and the support structure and compensate. Such relative movements can for example, in the combustion chamber of a gas turbine, in particular an annular combustion chamber, by different thermal expansion behavior the materials used and pulsations in the combustion chamber, during an irregular combustion can arise to produce the hot working medium, be caused. At the same time, the separating layer causes that the relatively inelastic heat shield element as a whole area on the release layer and the metallic support structure rests, since the heat shield element partially in the release layer penetrates. The release layer can be so production-related Unevenness on the support structure and / or the heat shield element, locally to an unfavorable point force entry can lead, balance.

Especially in the case of walls of high-temperature gas reactors, such as z. Pressurized gas turbine combustors, have their bearing with suitable combustion chamber liners Protected structures against a hot gas attack. ceramic Materials are available in comparison to metallic ones Materials due to their high temperature resistance, Corrosion resistance and low thermal conductivity ideally.

Due to material thermal expansion properties under im Under operating conditions typically occurring temperature differences (Ambient temperature at standstill, maximum Temperature at full load) the thermal mobility has to be ceramic Heat shields guaranteed as a result of temperature-dependent stretching be, so no component-destructive thermal stresses due to expansion inhibition. This can be achieved be protected by the hot gas attack Wall through a variety of limited in size, individual ceramic heat shields, z. B. heat shield elements from a technical ceramics, is lined. As already discussed above in connection with EP 0 419 487 B1 between the individual ceramic heat shield elements appropriate expansion gaps are provided, for security reasons in the hot state according to design never completely may be closed. It has to be ensured that the hot gas does not have the expansion wall the supporting wall structure overheated. The easiest and safest way to avoid this in a gas turbine combustor is included the rinsing of the expansion gaps with air, so-called blocking air cooling. For this purpose, the air can be used, anyway for cooling of support elements for the ceramic Heat shields is required.

The invention is based on the object, a heat shield element specify that a high strength at a particular have a long life. Furthermore, a special Low-maintenance combustion chamber and a gas turbine with a be specified such combustion chamber.

With respect to the heat shield element, this object is achieved according to the invention dissolved with a solidified poured one formed ceramic material body, in a number is introduced by reinforcing elements.

The invention is based on the consideration that a for a particularly long life designed heat shield element in particular to the extreme conditions of use should be adjusted. To make this possible and a special one high number of degrees of freedom for individual adaptation measures To provide, is moving away from the past customary production of the heat shield elements by pressing now a preparation provided by pouring. Indeed could be due to a cast ceramic heat shield a comparatively low tensile strength in particular in the longitudinal and transverse direction of the heat shield element the life be limited by the heat shield element. Order therefore a heat shield element based on a cast base to use the achievable design Degrees of freedom for use in a combustion chamber usable too should make for a long life and increased passive safety special measures for structural reinforcement of the main body are made, in particular also the cohesion of the main body in case of a possible Improve cracking.

Especially for increased tensile strength and reduction of crack lengths caused by thermal and thermomechanical Stress could occur, therefore, reinforcing elements provided in the body of the heat shield element are integrated. These reinforcing elements should firmly connected to the heat shield element to the material property of the tensile strength of the reinforcing elements to transfer to the heat shield element. These Function is positioned by those within the heat shield elements Reinforced elements fulfilled by the ceramic Casting material poured into the body and characterized are firmly connected to this or with the ceramic.

Advantageously, those with the use of a casting technique associated constructive degrees of freedom in the Design of the heat shield elements used in particular for by suitable geometries or local variations of characteristic material parameters a particularly high load capacity even with changing thermal loads of To ensure heat shield element.

In order for a reinforcing element is adapted to the high temperatures to which a heat shield element is exposed, and also connects firmly in the casting process with the ceramic casting material, the respective reinforcing element is advantageously formed of a ceramic material, preferably of an oxide ceramic material with an Al ₂ O ₃ Content of at least 60% by weight and with an SiO ₂ content of at most 20% by weight. This has a comparatively high tensile strength and combines due to the similar ceramic materials in solidification with the ceramic casting material. In addition, the thermal expansion of the reinforcing material is similar to the remaining ceramic material of the heat shield element, so that no adverse stresses occur in the heat shield element with temperature changes. Furthermore, the reinforcing element may advantageously be made of ceramic fibers such as CMC materials or structural ceramic material having a pore content of at most 10%.

The respective reinforcing element is preferably of the type a long, round ceramic rod in the style of a Reinforcement performed. To a reinforcing element especially firmly integrated into a heat shield element and around the reinforcing element as stiff as possible, this has expediently a number of beads and thickenings on. Over this is the reinforcing element in the surrounding Anchored ceramic material, which increases the tensile strength of Reinforcement element on the entire heat shield element transfers. In rod-shaped configuration, the reinforcing element especially at its end areas Have thickening, so that results in a bone shape. By such thickened ends or by rib-like Thickening becomes a positive connection between Reinforced element and body ensured. alternative or in addition, this compound can also be non-positively, for example via a sintering process or a grain, be executed.

To reinforce a heat shield element over the entire area, can a reinforcing element expediently also be designed plate-shaped, in particular a parallel and spaced from the surface of the heat shield element arranged flat plate can be provided. It can each a plate on the working medium side facing be positioned during the cooler side of the heat shield element also assigned a plate for reinforcement is.

In order to have as strong a material as possible between one Plate formed reinforcing element and the surrounding To reach ceramic material, has such a plate advantageously a number of recesses. Thereby can during the casting process of the heat shield element, the ceramic Gießmasse get into the recesses and also there solidify. The plate can in particular as a perforated plate be executed, where number, size and positioning the holes expediently depending on input purpose and material parameters are selected appropriately.

In an alternative or additional advantageous embodiment has a reinforcing element of a heat shield element preferably a grid structure on. In this case, the grid elements one with diamond-shaped or square cutouts train structured grid. A reinforcing element can also be formed by a plate, the circular Has recesses that are evenly spaced from each other are positioned so that a grid-shaped structure arises.

To solidify a heat shield element especially on the sides or reinforce, a reinforcing element is suitably rod-shaped and along a peripheral edge positioned the heat shield element.

To the structural integrity of the heat shield element itself at the onset of cracking over its entire circumference To ensure has a reinforcing element preferably an annular closed shape and extends along the circumference of the heat shield element.

To the strength of such an annular reinforcing element and thus the heat shield element still too increase or possibly warp-resistant is one Reinforcing element expediently as a circular ring executed.

For stabilization and consolidation of the corners of a heat shield element has a reinforcing element advantageously a cruciform shape, with the ends in the region of Corners of the heat shield element are positioned. For one suitable bracing of the cross-shaped reinforcing element in the heat shield elements, which can increase the tensile strength the ends of the cross-shaped reinforcing element thickened be such that the reinforcing element in the heat shield element is anchored.

Conveniently, heat shield elements are those described above Type components of the inner lining of a combustion chamber. This combustion chamber is advantageously part of a Gas turbine. The combustion chamber could be silo-shaped Combustion chamber or as from several smaller combustion systems However, the composite combustion chamber is designed to be preferably formed as an annular combustion chamber.

The advantages achieved by the invention are in particular in the possibility of resorting to a casting process with the possible creative degrees of freedom To produce heat shield elements that are particularly high Have tensile strength. Through the integration of reinforcing elements in heat shield elements made of a cast ceramic material, it is possible the material properties the reinforcing elements in particular to transfer the tensile strength to a heat shield element. The shape of a heat shield element can be flexible being held. Another advantage is that through the choice of different embodiments of reinforcing elements and the positioning of these in the heat shield element an individual adaptation to the on a heat shield element acting thermal and mechanical Loads is possible. Due to the increased strength The heat shield elements also extends the life a heat shield element, since the spread of Cracks reduced and the structural integrity of the component (passive safety) is increased.

The advantage of a casting process is the possibility of produce more complex forms of heat shield elements. So on the one hand, the outer basic shape comparatively easily and inexpensively varied. On the other hand, it is at one Casting possible, fixtures the heat shield elements on the combustion chamber wall with pour. For example, in cast heat shield elements Grooves, holes, threads or mounting devices be poured.

FIG 1

einen Halbschnitt durch eine Gasturbine,

FIG 2

die Brennkammer der Gasturbine nach FIG 1,

FIG 3

ein Hitzeschildelement mit plattenförmigen Verstärkungselementen,

FIG 4

ein Hitzeschildelement mit einem gitterförmigen Verstärkungselement,

FIG 5

ein Hitzeschildelement mit stabförmigen Verstärkungselementen,

FIG 6

ein Hitzeschildelement mit einem ringförmigen Verstärkungselement, und

FIG 7

ein Hitzeschildelement mit einem kreuzförmigen Verstärkungselement.

An embodiment of the invention will be explained in more detail with reference to a drawing. Show:

FIG. 1

a half-section through a gas turbine,

FIG. 2

the combustion chamber of the gas turbine according to FIG. 1,

FIG. 3

a heat shield element with plate-shaped reinforcing elements,

FIG. 4

a heat shield element with a grid-shaped reinforcing element,

FIG. 5

a heat shield element with rod-shaped reinforcing elements,

FIG. 6

a heat shield element with an annular reinforcing element, and

FIG. 7

a heat shield element with a cross-shaped reinforcing element.

Identical parts are given the same reference numerals in all figures Mistake.

The gas turbine 1 according to FIG. 1 has a compressor 2 for Combustion air, a combustion chamber 4 and a turbine 6 for Drive of the compressor 2 and a generator, not shown or a work machine. These are the turbine 6 and the compressor 2 on a common, as a turbine rotor designated turbine shaft 8 is arranged, with the also the generator or the work machine is connected, and which is rotatably mounted about its central axis 9. In the the type of an annular combustion chamber running combustion chamber 4 is with a number of burners 10 for burning a liquid or gaseous fuel.

The turbine 6 has a number of with the turbine shaft. 8 connected, rotatable blades 12. The blades 12 are arranged in a ring on the turbine shaft 8 and thus form a number of blade rows. Farther The turbine 6 includes a number of stationary vanes 14, which is also coronal under the formation of Guide vane rows attached to an inner housing 16 of the turbine 6 are. The blades 12 serve to drive the turbine shaft 8 by momentum transfer from the turbine. 6 flowing through the working medium M. The guide vanes 14 serve however, to the flow of the working medium M between two seen in the flow direction of the working medium M. successive rows of blades or blade rings. A successive pair of a wreath of Vanes 14 or a row of vanes and one Wreath of blades 12 or a blade row is also referred to as turbine stage.

Each vane 14 has a so-called blade root Platform 18 on, which fixes the respective vane 14 on the inner housing 16 of the turbine 6 as a wall element is arranged. The platform 18 is a thermal comparatively heavily loaded component, which is the outer boundary a Heizgaskanals for the turbine 6 flowing through Working medium M forms. Each blade 12 is in analog Way about referred to as a blade root platform 20th attached to the turbine shaft 8.

Between the spaced apart platforms 18 of the vanes 14 of two adjacent rows of vanes is in each case a guide ring 21 on the inner housing 16 of Turbine 6 arranged. The outer surface of each guide ring 21 is also the hot, the turbine 6 flowing through Working medium M exposed and in the radial direction from the outer end 22 of the blade opposite it 12 spaced by a gap. The between adjacent Guide blade rows arranged guide rings 21st serve in particular as cover elements that the inner wall 16 or other housing-mounted components before a thermal Overuse by the turbine 6 flowing through hot Working medium M protects.

The combustion chamber 4 is in the embodiment, as shown in FIG represented, designed as a so-called annular combustion chamber, in the case of a plurality of circumferentially around the turbine shaft 8 around arranged burners 10 in a common Combustor chamber lead. For this purpose, the combustion chamber 4 in her Entity as an annular structure designed around the Turbine shaft 8 is positioned around.

To achieve a comparatively high efficiency the combustion chamber 4 for a comparatively high temperature the working medium M of about 1200 ° C to 1500 ° C designed. Even with these unfavorable for the materials operating parameters to allow a comparatively long service life is the combustion chamber wall 24 on the working medium M facing side with a heat shield elements 26th provided inner lining. Due to the high temperatures inside the combustion chamber 4 is for the heat shield elements 26 provided a cooling system.

The heat shield elements 26 are especially for a long time Lifetime designed so as to minimize damage by the extreme influences, such as the high temperature and vibration the combustion chamber 4, occur. These exist from a formed of a cast ceramic material Base 28, integrated in the reinforcing elements 30 are. For a suitable temperature resistance of the reinforcing elements These consist of a ceramic material or composite material. The reinforcing elements 30 can do so for the influences acting on a heat shield element 26 influences be interpreted. In the figures 3 to 7 are different Embodiments of heat shield elements 26 with reinforcing elements 30 listed.

In FIG. 3, a heat shield element 26 is plate-shaped Reinforcement elements 30 shown, wherein in each case for the the working medium M and the cooled side facing Surface a reinforcing element 30 is provided. In 4 it can be seen that the plate-shaped reinforcing elements 30 for a better bond with the surrounding ceramic can be provided with a grid-shaped structure or are designed as a grid, in particular as a cross grid (FIG 4a) or as a perforated grid (FIG 4b).

For a particularly high reinforcement of the edge areas of a Heat shield element 26 can, as shown in FIG 5, rod-shaped reinforcing elements 30 are used, the run along the side edges of a heat shield element 26 and with beads or thickenings (FIG. 5a) or compressed Ends (FIG 5b) are provided to a solid anchorage in the surrounding ceramics 28. Out FIG. 6 shows that for a reinforcement of a heat shield element 26 along its circumference an annular Structure (FIG 6a) of the reinforcing elements 30 are used can, taking these in a particularly torsion-resistant Execution circular (FIG 6b) may be executed. In the in FIG. 7 shows a heat shield element 26 that stabilizes it acting tension of the corners of a heat shield element 26 a cross-shaped reinforcing element 30 is provided, that at its ends each thickenings for anchoring in the ceramic material 26 has.

Claims (11)

Heat shield element (26), in particular for the inner lining the combustion chamber (4) of a gas turbine (1), with a formed from a solidified cast ceramic material Main body (28), in which a number of reinforcing elements (30) is introduced. A heat shield element (26) according to claim 1, wherein the or each reinforcing element (30) made of a ceramic composite material is formed. A heat shield element (26) according to claim 1 or 2, wherein the or each reinforcing element (30) has a number of beads and or has thickenings. Heat shield element (26) according to one of claims 1 to 3, wherein the or each reinforcing element (30) is parallel and spaced from the surface of the base body (28) includes flat plate. A heat shield element (26) according to claim 4, whose plate-shaped formed reinforcing element (30) a number of Has recesses. Heat shield element (26) according to one of claims 1 to 5, wherein the or each reinforcing element (30) has a grid structure having. Heat shield element (26) according to one of claims 1 to 3, whose reinforcing element (30) has a rod-shaped form and along a peripheral edge of the base body (28) extends. Heat shield element (26) according to one of claims 1 to 3, whose reinforcing element (30) has a cruciform shape, the ends being in the area of the corners of the main body (28) are positioned. Heat shield element (26) according to one of claims 1 to 3, its reinforcing element (30) has an annular closed Has shape and along the circumference of the main body (28) runs. Combustion chamber (4) with an inner wall lining of heat shield elements (26) according to one of claims 1 to 9. Gas turbine (1) with a combustion chamber (4) according to claim 10th

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