Combustion chamber assembly with different curvatures for a combustion chamber wall and a combustion chamber shingle fixed thereto

Abstract

A combustion chamber assembly group, and a mounting method therefor, includes a combustion chamber for an engine that includes a curved combustion chamber wall extending along two spatial directions, and a combustion chamber shingle affixed at an inner side of the combustion chamber wall and having a shingle edge defining the outer contour of the shingle. For an at least sectional abutment of the shingle edge at the combustion chamber wall with a minimum clamping force in an operational state of the engine, the shingle is mounted to the combustion chamber wall in a mounting state in which the shingle at least at one section of the shingle edge has a curvature with respect to at least one of the spatial directions that differs from the curvature of the combustion chamber wall with respect to this spatial direction.

Claims

1. A combustion chamber assembly group, comprising: a combustion chamber for an engine that comprises a curved combustion chamber wall extending along two spatial directions, and a combustion chamber shingle that is affixed at an inner side of the combustion chamber wall and has a shingle edge that defines an outer contour of the combustion chamber shingle, the shingle edge including a central portion and end portions positioned on opposite sides of the central portion, wherein for an at least sectional abutment of the shingle edge at the combustion chamber wall at a minimum clamping force in an operational state of the engine, the combustion chamber shingle has a curvature at a section of the shingle edge that differs with respect to at least one of the two spatial directions from a curvature of the combustion chamber wall with respect to the at least one of the two spatial directions, in a mounting state in which the combustion chamber shingle is mounted at the combustion chamber wall; wherein the end portions of the shingle edge remain in contact with the combustion chamber wall from the mounting state to the operational state and the difference between the curvature of the section of the shingle edge and the combustion chamber wall changes between the mounting state and the operational state to provide the minimum clamping force in the operational state of the engine, wherein with respect to one of the two spatial directions, the curvature of the shingle edge is smaller than the curvature of the combustion chamber wall, and wherein with respect to the other of the two spatial directions, the curvature of the shingle edge is larger than the curvature of the combustion chamber wall between the end portions.

2. The combustion chamber assembly group according to claim 1, wherein a ratio between the curvature of the combustion chamber wall and the smaller curvature at the section of the shingle edge is in a range from 1.03 to 1.4.

3. The combustion chamber assembly group according to claim 2, wherein the ratio between the curvature radius of the combustion chamber wall and the curvature radius at the section of the shingle edge is in a range from 1.03 to 1.2.

4. The combustion chamber assembly group according to claim 1, wherein a ratio between the curvature of the combustion chamber wall and the larger curvature at the section of the shingle edge is in a range from 0.7 to 0.98.

5. The combustion chamber assembly group according to claim 1, wherein the section of the shingle edge includes a first section and a second section and a first curvature radius at the first section of the shingle edge is larger with respect to a first spatial direction of the two spatial directions along which the combustion chamber wall extends than the curvature radius of the combustion chamber wall with respect to the first spatial direction, and a second curvature radius at the second section of the shingle edge is smaller with respect to a second spatial direction of the two spatial directions than the curvature radius of the combustion chamber wall with respect to the second spatial direction.

6. The combustion chamber assembly group according to claim 1, wherein the section of the shingle edge includes a first section and a second section and a first curvature radius at the first section of the shingle edge is larger with respect to a first spatial direction of the two spatial directions along which the combustion chamber wall extends than the curvature radius of the combustion chamber wall with respect to the first spatial direction, and a second curvature radius at the second section of the shingle edge is also larger with respect to a second spatial direction of the two spatial directions than the curvature radius of the combustion chamber wall with respect to the second spatial direction.

7. The combustion chamber assembly group according to claim 1, wherein the combustion chamber wall extends along an axial direction which is parallel to a flow direction through the combustion chamber, and along a circumferential direction that extends along a circular path about the axial direction.

8. A gas turbine engine with a combustion chamber that comprises at least one combustion chamber assembly group according to claim 1.

9. A method for producing a combustion chamber assembly group, comprising: providing a combustion chamber for an engine that comprises: a curved combustion chamber wall extending along two spatial directions, and a combustion chamber shingle that is to be affixed at an inner side of the combustion chamber wall and has a shingle edge that defines the outer contour of the combustion chamber shingle, the shingle edge including a central portion and end portions positioned on opposite sides of the central portion, wherein for a sectional abutment of the shingle edge at the combustion chamber wall with a minimum clamping force in an operational state of the engine, the combustion chamber shingle is mounted to the combustion chamber wall in a mounting state in which the combustion chamber shingle at a section of the shingle edge has a curvature with respect to at least one of the two spatial directions that differs by a predetermined measure from a curvature of the combustion chamber wall with respect to the at least one of the two spatial directions; wherein the end portions of the shingle edge remain in contact with the combustion chamber wall from the mounting state to the operational state and the difference between the curvature of the section of the shingle edge and the combustion chamber wall changes between the mounting state and the operational state to provide the minimum clamping force in the operational state of the engine, wherein with respect to one of the two spatial directions, the curvature of the shingle edge is smaller than the curvature of the combustion chamber wall, and wherein with respect to the other of the two spatial directions, the curvature of the shingle edge is larger than the curvature of the combustion chamber wall between the end portions.

10. The method according to claim 9, wherein the predetermined measure is determined depending on at least one chosen from a strength of the minimum clamping force, a natural frequency of the combustion chamber shingle, and on a temperature difference between the combustion chamber shingle and the combustion chamber wall in the operational state of the engine.

11. The method according to claim 9, wherein the predetermined measure is chosen in such a manner that a vibration of the section of the combustion chamber shingle relative to the combustion chamber wall is prevented in the operational state of the engine.

12. The method according to claim 9, wherein, the combustion chamber shingle is deformed and correspondingly curved to obtain the different curvature radii of the combustion chamber wall and the combustion chamber shingle.

13. The method according to claim 9, wherein the curvature radii of the combustion chamber wall and the combustion chamber shingle are adjusted to each other in order to obtain the sectional abutment of the section of the shingle edge with the minimum clamping force.

14. A combustion chamber assembly group, comprising: a combustion chamber for an engine that comprises a curved combustion chamber wall extending along two spatial directions, and a combustion chamber shingle that is affixed at an inner side of the combustion chamber wall and has a shingle edge that defines an outer contour of the combustion chamber shingle, the shingle edge including a central portion and end portions positioned on opposite sides of the central portion, wherein for an at least sectional abutment of the shingle edge at the combustion chamber wall at a minimum clamping force in an operational state of the engine, the combustion chamber shingle has a curvature at a section of the shingle edge that differs with respect to at least one of the two spatial directions from a curvature of the combustion chamber wall with respect to the at least one of the two spatial directions, in a mounting state in which the combustion chamber shingle is mounted at the combustion chamber wall; wherein the end portions of the shingle edge remain in contact with the combustion chamber wall from the mounting state to the operational state and the difference between the curvature of the section of the shingle edge and the combustion chamber wall changes between the mounting state and the operational state to provide the minimum clamping force in the operational state of the engine, wherein the section of the shingle edge includes a first section and a second section, a first curvature extending between two of the end points at the first section of the shingle edge is smaller, with respect to a first spatial direction of the two spatial directions along which the combustion chamber wall extends, than the curvature of the combustion chamber wall extending between the two end points of the first curvature with respect to the first spatial direction, and a second curvature extending between two of the end points at the second section of the shingle edge is also smaller, with respect to a second spatial direction of the two spatial directions, than the curvature of the combustion chamber wall extending between the two end points of the second curvature with respect to the second spatial direction.

Description

(1) The accompanying Figures illustrate possible embodiment variants of the proposed solution by way of example.

(2) Herein:

(3) FIG. 1A shows, in sections and in a side view, a radially inner combustion chamber wall of an embodiment variant of a proposed combustion chamber assembly group with a combustion chamber shingle affixed thereat, which in the axial direction has a smaller curvature than the radially inner combustion chamber wall;

(4) FIG. 1B shows the combustion chamber assembly group of FIG. 1A in a perspective view;

(5) FIG. 2 shows, in a perspective view, a combustion chamber assembly group, illustrating the different curvature lines for a shingle edge of the combustion chamber shingle, on the one hand, and the radially inner combustion chamber wall, on the other hand, also showing the curvature of the combustion chamber shingle by way of comparison, which in the cold mounting state of the combustion chamber assembly group corresponds to the curvature of the radially inner combustion chamber wall;

(6) FIG. 3 shows an illustration of different curvature radiuses of the radially inner combustion chamber wall and the combustion chamber shingle corresponding to the embodiment variant of FIGS. 1A and 1B;

(7) FIG. 4A shows a schematic sectional view of a gas turbine engine in which the proposed combustion chamber assembly group is used;

(8) FIG. 4B shows a schematic sectional view of a combustion chamber of the gas turbine engine of FIG. 4A;

(9) FIG. 4C shows, in sections, an enlarged sectional view of a combustion chamber with a combustion chamber shingle;

(10) FIG. 5 shows a flowchart for an embodiment variant of a proposed manufacturing method.

(11) FIG. 4A schematically illustrates, in a sectional view, a (turbofan) engine T in which the individual engine components are arranged in succession along a rotational axis or central axis M and the engine T is embodied as a turbofan engine. By means of a fan F, air is suctioned in along an entry direction at an inlet or an intake E of the engine T. This fan F, which is arranged inside a fan housing FC, is driven by means of a rotor shaft S that is set into rotation by a turbine TT of the engine T. Here, the turbine TT connects to a compressor V, which for example has a low-pressure compressor 111 and a high-pressure compressor 112, and where necessary also a medium-pressure compressor. The fan F supplies air to the compressor V in a primary air flow F1, on the one hand, and, on the other, to a secondary flow channel or bypass channel B in a secondary air flow F2 for creating a thrust. Here, the bypass channel B extends about a core engine that comprises the compressor V and the turbine TT, and also comprises a primary flow channel for the air that is supplied to the core engine by the fan F.

(12) The air that is conveyed by means of the compressor V into the primary flow channel is transported into the combustion chamber section BKA of the core engine where the driving power for driving the turbine TT is generated. For this purpose, the turbine TT has a high-pressure turbine 113, a medium-pressure turbine 114, and a low-pressure turbine 115. The turbine TT drives the rotor shaft S and thus the fan F by means of the energy that is released during combustion in order to generate the necessary thrust by means of the air that is conveyed into the bypass channel B. The air from the bypass channel B as well as the exhaust gases from the primary flow channel of the core engine are discharged by means of an outlet A at the end of the engine T. Here, the outlet A usually has a thrust nozzle with a centrally arranged outlet cone C.

(13) FIG. 3B shows a longitudinal section through the combustion chamber section BKA of the engine T. Here, in particular an (annular) combustion chamber BK of the engine T can be seen, which forms an embodiment variant of a proposed combustion chamber assembly group. A nozzle assembly group is provided for injecting fuel or an air-fuel-mixture into a combustion space 30 of the combustion chamber BK. It comprises a combustion chamber ring along which multiple fuel nozzles 2 are arranged along a circular line about the central axis M. Here, the nozzle exit openings of the respective fuel nozzles 2 that are positioned at the combustion chamber ring are provided at the combustion chamber ring R. Here, each fuel nozzle 2 comprises a flange by means of which a fuel nozzle 2 is screwed to an outer housing 22 of the combustion chamber section BKA.

(14) The enlarged sectional view of FIG. 4C shows a more detailed rendering of an embodiment of a combustion chamber BK of the combustion chamber section BKA. Here, the combustion chamber BK comprises the fuel nozzle 2 that is supported in a combustion chamber head. Via the fuel nozzle 2, fuel is injected into the combustion space 30 of the combustion chamber BK. The exhaust gases of the mixture that is combusted inside the combustion space 30 are transported in the axial direction x via a preliminary turbine guide row 33 to the high-pressure turbine 113 to set the turbine stages in rotation.

(15) The combustion space 30 is delimited by—with respect to the central M of the engine T—radially inner and radially outer combustion chamber walls 32a, 32b of a combustion chamber housing of the combustion chamber BK which respectively extend along the axial direction x, on the one hand, and, on the other hand, along a circumferential direction φ about this axial direction x. The combustion chamber walls 32a and 32b thus extend along the axial direction x along the central axis M as well as along the circumferential direction φ. A radial direction r extends perpendicular to the axial direction x as well as to the circumferential direction φ. Along this radial direction r, air may flow via admixing holes 35 into the combustion space 3, for example.

(16) Arranged at the inside at the combustion chamber walls 32a, 32b are combustion chamber shingles 34a, 34b. The combustion chamber walls 32a, 32b thus enclose the combustion space 30 of the combustion chamber BK and support the combustion chamber shingles 34a, 34b with which the combustion chamber walls 32a, 32b is cladded in order to facilitate additional cooling and to withstand the high temperatures that are present inside the combustion space 30.

(17) Here, the combustion chamber shingles 34a, 34b are respectively supported by means of one or multiple bolts 4 at the respective inner or outer combustion chamber wall 32a, 32b. At that, each bolt 4 passes through an opening at the combustion chamber wall 32a or 32b, and is affixed at the combustion chamber wall 32a or 32b by means of respectively one nut 5. For example, cooling of the respective combustion chamber shingle 34a or 34b is facilitated via multiple effusion cooling holes that are provided at the combustion chamber shingle 34a or 34b. In addition, the combustion chamber shingle 34a, 34b can have at least one admixing hole 35 through which air from the surrounding exterior space can flow into the combustion space 30. Here, the air that flows through the admixing hole 35 serves for cooling and/or leaning the combustion.

(18) Here, the exterior space that surrounds the combustion chamber BK, for example in the form of an annular channel, forms an air supply 36 for the admixing holes 35 (and any effusion cooling holes that may be present). At that, air that flows into the combustion chamber BK along an inflow direction Z is divided in the area of the fuel nozzle 2 by a section that is designed in a hood-like manner into a primary airflow for the combustion space 30 and a secondary airflow for the surrounding exterior space with the air supply 36. Here, the air usually flows into the combustion chamber BK via diffusor (not shown).

(19) The fixation of the combustion chamber shingles 34a, 34b at a combustion chamber wall 32a, 32b is realized by means of a bolt 4, which may e.g. formed integrally with a combustion chamber shingle 34a or 34b, as illustrated in FIGS. 1B and 2 by way of example for an inner combustion chamber shingle 34a. Here, a bolt shaft of a bolt 4 that is formed at the inner side of the combustion chamber shingle 34a has a thread at its top end. The combustion chamber shingle 34a is affixed at the combustion chamber wall 32a according to the intended use by the bolt shaft being passed through an opening at the combustion chamber wall 32a and being screwed onto a nut 5 from the outside, so that the combustion chamber shingle 34a is supported internally against the combustion chamber wall 32a.

(20) The support of the combustion chamber shingles 34a or 34b against the respective combustion chamber wall 32a or 32b can strongly depend on the operational state of the engine T. If no abutment at the respective combustion chamber wall 32a or 32b is provided at the shingle edge 341 of a combustion chamber shingle 32a, 32b, a section of the combustion chamber shingle 34a or 34b may be able to vibrate freely during operation of the engine. In the case of high-frequency vibrations, such a possibility of free vibration may lead to a heightened risk of failure due to fatigue failure. To prevent vibration in particular of an edge-side section of the combustion chamber shingle 34a 34b relative to the combustion chamber wall 32a, 32b at which the combustion chamber shingle 34a, 34b is affixed, it is therefore provided in a proposed solution that, in a cold mounting state, the combustion chamber shingle 34a, 34b and the combustion chamber wall 32a, 32b have curvatures that differ from each other by a predetermined measure with respect to at least one of the spatial directions x and φ, along which the combustion chamber wall 32a or 32b extends.

(21) According to the proposed solution, at least at one circumferential shingle edge 341, a combustion chamber shingle 34a or 34b is provided with a curvature Δκ that differs in the cold mounting state from a curvature of a combustion chamber wall 32a or 32b at which the combustion chamber shingle 34a or 34b is affixed. However, in principle also a shingle base body 340 circumferentially surrounded by the shingle edge 341 may be correspondingly curved. Here, the curvature differences between a combustion chamber shingle 34a, 34b and the associated combustion chamber wall 32a or 32b are in particular determined by the strength of a minimum clamping force K with which a shingle edge 341 of a combustion chamber shingle 34a, 34b is to abut an associated combustion chamber wall 32a or 32b during operation of the engine T, on a natural frequency of the combustion chamber shingle 34a, 34b, and/or on a temperature difference between the combustion chamber shingle 34a, 34b and the combustion chamber wall 32a, 32b during operation of the engine T—with the thermal expansion coefficients of the combustion chamber shingle 34a, 34b and the combustion chamber wall 32a, 32b being known—, and thus on the mechanical and thermal loads that act during operation of the engine T, including the occurring thermal deformations at the combustion chamber wall 32a, 32b and the combustion chamber shingle 34a, 34b. Here, the different curvatures of the combustion chamber wall 32a, 32b, on the one hand, and the combustion chamber shingle 34a, 34b at its shingle edge 341, on the other hand, are adjusted to each other in such a manner that, during operation of the engine T and thus at predefined operating points of the engine T, an abutment of the shingle edge 341 of a combustion chamber shingle 34a, 34b with a minimum clamping force is ensured at least in certain sections and free vibration of the combustion chamber shingle 34a, 34b is prevented at least in the section of the shingle band 341 that abuts with the minimum clamping force.

(22) FIGS. 1A and 1B show a possible geometry of the inner combustion chamber shingle 34a and the inner combustion chamber wall 32a in different views. In particular along the axial direction x, the inner combustion chamber shingle 34a has a curvature κ.sub.34 that is smaller than a curvature κ.sub.32 of the inner combustion chamber wall 32a in the axial direction x. Here, the curvature differences are chosen in such a manner that the combustion chamber shingle 34a is always pressed against the inner side of the combustion chamber wall 32a at least with a minimum clamping force K in the operational state of the engine T (at predefined operating points). At that, a radius of the combustion chamber wall 32a may for example be approximately 220 mm, while the radius of the shingle edge 341 along the axial direction x is in the range of about 230 mm. This results in a curvature κ.sub.32 of the combustion chamber wall 32a along the axial direction x in the range of approximately 4.5×10.sup.−3 and a curvature κ.sub.34 of the shingle edge 341 (as well as possibly also of the shingle base body 340) along the axial direction x in the range of 4.3×10.sup.−3. A ratio Δκ between the curvature of the combustion chamber wall 32a κ.sub.32 and the curvature of the shingle edge 341 of the combustion chamber shingle 34a κ.sub.34 is thus approximately 1.045.

(23) Thus, in the (cold) mounting state of the combustion chamber assembly group, a curvature of a combustion chamber shingle 34a or 34b corresponding to FIGS. 1A and 1B does not follow a curvature of a combustion chamber wall 34a or 34b at which the combustion chamber shingle 34a or 34b is to be affixed. The curvatures are in particular chosen to differ in such a manner that an abutment of the shingle edge 341 at the combustion chamber wall 32a or 32b with a contact pressure is always ensured through the provided operating points of the engine T. For this purpose, the respective combustion chamber shingle 34a, 34b is for example correspondingly deformed, given a predefined geometry of the combustion chamber wall 32a or 32b.

(24) FIG. 2 provides a perspective rendering in which the curvature differences are illustrated based on the curvature lines k.sub.34x and k.sub.32x which are followed by the curvature of the combustion chamber wall 32a or of a shingle edge 341 of the combustion chamber shingle 34a. The combustion chamber shingle 34a or 34b, which is pre-curved in a manner that differs from the geometry of the associated combustion chamber wall 32a or 32b, does not follow the curvature of the combustion chamber wall 32a or 32b in the mounting state. In this context, it is in particular conceivable that a circumferential shingle edge 341 of a combustion chamber shingle 34a or 34b is not in any contact with the combustion chamber wall 32a or 32a after mounting, and thus when the engine T is not in operation, and the predefined abutment under contact pressure occurs only through the loads exerted from the outside and/or the developing temperature field in the combustion chamber shingle 34a, 34b and the combustion chamber wall 32a, 32b due to the resulting deformations.

(25) Referring to FIGS. 1A and 1B, FIG. 3 illustrates by way of example different curvature radiuses for the inner combustion chamber wall 32a, on the one hand, and the inner combustion chamber shingle 34a, on the other hand, with respect to the axial direction x. In the shown variant, a curvature radius D.sub.32/2 of the combustion chamber wall 32a may for example be approximately 220 mm, and thus a curvature is approximately 4.5×10.sup.−3, while a curvature radius D.sub.34/2 of the shingle edge 341 of the combustion chamber shingle 34a is approximately 230 mm, and thus a curvature is approximately 4.3×10.sup.−3.

(26) However, corresponding to the shown embodiment variants of FIGS. 1A to 3, a shingle edge 341 of a combustion chamber shingle 34a or 34b can thus have a curvature that differs from the combustion chamber wall 32a or 32b not only along the axial direction x, but also along the circumferential direction φ. For example, the following may apply to a curvature ratio Δκ between a curvature κ.sub.32 of the combustion chamber wall 32a, 32b and a curvature κ.sub.34 of a shingle edge 341 of a combustion chamber shingle 34a, 34b that is affixed thereat depending on the spatial direction x or φ—respectively with regards to a (cold) mounting state of the combustion chamber assembly group: 1. for an inner combustion chamber shingle 34a in the axial direction (axis direction)×1.03≤Δκ<1.4 and in the circumferential direction φ0.7<Δκ≤0.98, with Δκ=κ.sub.32/κ.sub.34; and 2. for an outer combustion chamber shingle 34b in the axial direction (axis direction) x as well as in the circumferential direction φ1.03≤Δκ<1.4, with Δκ=κ.sub.32/κ.sub.34.

(27) Once again schematically illustrated based on the flow chart of FIG. 5 is a possible flow of an embodiment variant of a proposed manufacturing method by means of which also a combustion chamber assembly group can be produced corresponding to FIGS. 1A to 3, for example.

(28) Here, in a first method step A1, it is initially determined in a computer-aided manner based on the available operational data of the engine T and component data of the combustion chamber assembly group—in particular a natural frequency of a combustion chamber shingle 34a, 34b, thermal expansion coefficients of the combustion chamber shingle 34a, 34b and the combustion chamber wall 32a, 32b, as well as a temperature difference between the combustion chamber shingle 34a, 34b and the combustion chamber wall 32a, 32b that occurs during operation of the engine T—by which measure the curvatures of the combustion chamber wall 32a, 32b and of a shingle edge 341 of a combustion chamber shingle 34a or 34b have to differ from each other along the different spatial directions x and φ to ensure an abutment of the shingle edge 341 at the combustion chamber wall 32a or 32b with a predefined minimum clamping force K at least in certain sections of the shingle edge 341 during proper operation of the engine T. Based on the expected (calculated) deformations, a model for a basic geometry of the combustion chamber shingles 34a, 34b which are to be used in the combustion chamber BK is determined in a method step A2. In a method step A3, this model provides the basis for a deformation of the combustion chamber shingles 34a, 34b, so that the combustion chamber shingles 34a, 34b take the desired optimized abutment shape during the operative state. During operation of the engine T and in a state in which they are mounted at the combustion chamber wall 32a, 32b, the combustion chamber shingles 34a, 34b that are thus manufactured in a deformed manner will always abut the respective combustion chamber wall 32a or 32b with their shingle edge 341 with at least the minimum clamping force.

PARTS LIST

(29) 111 low-pressure compressor

(30) 112 high-pressure compressor

(31) 113 high-pressure turbine

(32) 114 medium-pressure turbine

(33) 115 low-pressure turbine

(34) 2 fuel nozzle

(35) 22 outer housing

(36) 32a, 32b inner/outer combustion chamber wall

(37) 33 preliminary turbine guide row

(38) 340 shingle base body

(39) 341 shingle edge

(40) 34a, 34b inner/outer combustion chamber shingle

(41) 35 admixing hole/mixed air hole

(42) 36 air supply

(43) 4 bolt

(44) 5 nut

(45) A outlet

(46) B bypass channel

(47) C outlet cone

(48) BK combustion chamber

(49) BKA combustion chamber section

(50) E inlet/intake

(51) F fan

(52) F1, F2 fluid flow

(53) FC fan housing

(54) K pressing force

(55) k.sub.32x, k.sub.34x curvature line

(56) M central/rotational axis

(57) S rotor shaft

(58) T (turbofan) engine

(59) TT turbine

(60) V compressor

(61) Z inflow direction