Patent Application
20180038244
This claims the benefit of German Patent Application DE102016213810.3, filed Jul. 27, 2016 and hereby incorporated by reference herein.
The present invention relates to a liner element of a hot-gas-conveying duct of a turbine intermediate case of a gas turbine, in particular of an aircraft gas turbine, the liner element including a first, axially forward connecting portion and a second, axially rearward connecting portion, a central portion connected to the first connecting portion and the second connecting portion and located axially therebetween; the central portion having an outer surface facing away from the duct; and the first connecting portion being couplable to axially forward components of the gas turbine, and the second connecting portion being couplable to axially rearward components of the gas turbine.
Directional words such as “axial,” “axially,” “radial,” “radially,” and “circumferential” are taken with respect to the machine axis of the turbine intermediate case or gas turbine, unless the context explicitly or implicitly indicates otherwise.
In the context of the present invention, the term “turbine intermediate case” includes casings which directly adjoin the casing of a turbine stage in the axial direction of the gas turbine, and preferably are disposed between two turbine stages. The gas turbine may have two or more turbine stages, depending on its design. Thus, the term “turbine case” includes in particular also a so-called “turbine center frame.”
It is known to provide stiffening ribs on components, in particular liner elements, of turbine intermediate cases or gas turbines. Generally, the known stiffening ribs extend in the axial direction or in the circumferential direction. The known stiffening ribs are coupled to edge portions of the respective component, so that the stiffening ribs generally extend along the entire component in the axial direction or in the circumferential direction. Such stiffening ribs do allow high stiffness to be achieved for the components; however, high thermal stresses are induced in the component due to the connection of the stiffening ribs to the edge portions. Moreover, such known stiffening ribs require a large amount of material.
It is-an object of the present invention to provide a liner element for an annular duct of a turbine intermediate case, which liner element provides sufficient stiffness using little material and makes it possible to reduce thermally induced stresses.
To achieve this object, it is proposed for the central portion to have at least one first reinforcement portion projecting in a direction away from the duct and extending substantially straight between an axial forward end and an axial rearward end; at least one of the two axial ends being adjoined by a second reinforcement portion projecting in a direction away from the duct and extending inclinedly or curvedly relative to the straight-line extent of the first reinforcement portion; the first reinforcement portion and the second reinforcement portion together forming a reinforcing element; the entire reinforcing element being disposed within the outer surface of the central portion, in particular in such a way that the reinforcing element is spaced apart from the first connecting portion and from the second connecting portion.
Thus, the first reinforcement portion, which extends substantially straight between the axial forward end and the axial rearward end, has a main direction of extension having an axial directional component; i.e., a directional component oriented in the axial direction of the turbomachine. Preferably, the main direction of extension of the first reinforcement portion has no circumferential directional component (i.e., directional component in the circumferential direction of the turbomachine), or a circumferential directional component that is smaller than the axial directional component.
By arranging two reinforcement portions in such a way that the second reinforcement portion extends inclinedly or curvedly relative to the first straight reinforcement portion and that the two reinforcement portions together form the reinforcing element, it is possible to achieve a material-saving design. Moreover, due to the distances from the connecting portions, it is possible to prevent constraints, and thus to prevent thermally induced stresses.
A free end of the first reinforcement portion which is not connected to a second reinforcement portion may be configured to taper at least in the radial direction such that the first reinforcement portion merges substantially continuously into the outer surface of the central portion. Thus, the free end of the first reinforcement portion forms a kind of seamless or smooth transition between the first reinforcement portion and the outer surface of the central portion.
The second reinforcement portion may be configured to be substantially symmetrical with respect to the first reinforcement portion connected thereto, in particular such that the first reinforcement portion and the second reinforcement portion form a Y-shaped reinforcing element. The free ends of the second reinforcement portion may in particular be oriented such that they point toward mounting points of the liner element, at which the liner element is connected to other structures of the turbine intermediate case or gas turbine. The symmetrical, in particular Y-like configuration is also particularly suitable for optimally distributing the acting forces and stresses.
The second reinforcement portion may have two free ends which are configured to taper at least in the radial direction such that the second reinforcement portion merges substantially continuously into the outer surface of the central portion. Thus, the entire reinforcing element, if formed, for example, by a first reinforcement portion and a second reinforcement portion, has three free ends, which merge substantially seamlessly or smoothly into the outer surface of the central portion.
The first reinforcement portion may be located substantially centrally on the central portion with respect to the circumferential direction. In particular, the central region of the central portion is subject to the largest deformations, in particular bending loads, caused by pressure differentials between the hot gas flowing in the annular duct and the secondary air system outside the annular duct. Accordingly, this central region should preferably be reinforced to counteract bending or bulging out of the central portion in the radial direction.
The first connecting portion, the second connecting portion and the central portion may be curved at least in the circumferential direction. On the one hand, the curvature serves to adapt the liner element with regard to the assembled condition of a turbine intermediate case. Generally, the liner of the annular duct is formed by a plurality of adjacent liner elements, so that it is advantageous if the individual liner elements already have a corresponding curvature.
The reinforcing element may be spaced in the circumferential direction from lateral edge portions of the liner element, which project from the outer surface of the central portion at least in the radial direction. Generally, such edge portions form the transition to a component which is adjacent thereto in the circumferential direction, in particular an adjacent liner element. If, in addition to the its spacing from the first and second connecting portions, the reinforcing element is also spaced from these edge portions, the entire reinforcing element is located only in the region of the (outer) surface of the central portion. This allows the central portion to be reinforced in the desired manner without thermally induced stresses being transmitted, to a great extent, to the edge portions or the two connection portions.
A second reinforcement portion may be disposed at each end of the first reinforcement portion, thereby forming a kind of a double Y or a kind of a stick figure without a head, with legs spread and arms raised. In this configuration, the first reinforcement portion is disposed centrally and the two second reinforcement portions each have two arms extending away from the first reinforcement portion.
The entire reinforcing element may be formed in one piece with the central portion of the liner element. This can be accomplished by using a suitable casting mold in which the reinforcing element is already accounted for. Preferably, the liner element is produced using a casting process. However, alternatively, the component could also completely or partly be produced using an additive process. Thus, for example, the reinforcing element may be formed on the outer surface of the central portion by laser build-up welding.
The present invention also relates to a turbine intermediate case for a gas turbine, in particular an aircraft gas turbine, having a hot-gas-conveying annular duct; the annular duct having a plurality of the above-described liner elements at the radially outer periphery thereof. The liner elements may be arranged to adjoin one another in the circumferential direction. Alternatively, liner elements of the above-described type and differently configured liner elements may be arranged alternately in the circumferential direction.
The present invention will now be described with reference to the accompanying figures by way of example and not by way of limitation.
A reinforcing element 22 is provided to prevent central portion 16 from being strongly deformed, in particular from bending or bulging out, due to pressure differentials between the hot gas flowing in the annular duct and the secondary air system outside the annular duct. Reinforcing element 22 includes a first reinforcement portion 24 and a second reinforcement portion 26. As can be seen from
Second reinforcement portion 26 includes two arms 30a and 30b, which extend inclinedly relative to first reinforcement portion 24. Thus, in the present embodiment, reinforcing element 22 is shaped like a Y. Second reinforcement portion 26 has two free ends 32a, 32b. These free ends 32a, 32b are also configured to taper in the radial direction. This also allows for a seamless or smooth transition into outer surface 20 of central portion 16. Reinforcing element 22; i.e., its reinforcement portions 24, 26, project from central portion 16; i.e., from outer surface 20, in the radial direction. Reinforcement portions 24, 26 form kind of ribs, which reinforce central portion 16 against bending loads. All reinforcement portions 24, 26 have an upper surface 34, as well as lateral surfaces 36 extending inclinedly or curvedly from the upper surface to outer surface 20 of central portion 16. Surface 34 has a maximum width B at each of the respective free ends 28, 32a, 32b. The maximum width is provided in particular in the region of transition from the respective reinforcement portion 24, 26 into outer surface 20.
The continuous transition from the outer surface into reinforcement portions 24, 26 allows for easy manufacture of central portion 16 and liner element 10 using a casting process. Due to the continuous transition in the region of free ends 28, 32a, 32b, reinforcing element 22 is formed only within outer surface 22, without direct contact to other, in particular load-bearing structural components, such as, for example, connecting portions 12, 14 or edge portions 18.
The axially rearward (second) reinforcement portion 126 in
The differently configured second reinforcement portions 126 shown in
The here presented liner element having a stiffening element makes it possible to provide sufficient stiffness for the central portion and the liner element using little material. Moreover, the thermally induced stresses in the liner element, in particular in the connecting portions and the edge portions, can be kept low because the reinforcing element is not directly connected to these portions.
| Number | Date | Country | Kind |
|---|---|---|---|
| DE102016213810.3 | Jul 2016 | DE | national |
