KR-20260065903-A - A turbomachine including a seal between an outer casing component and an inner casing component, and a method

Abstract

The present specification discloses a turbomachine comprising an outer casing component and an inner casing component received in the outer casing component and coupled to the outer casing component. A passage is provided between the inner casing component and the outer casing component, and a sealing array is positioned in the passage. The sealing array comprises an annular sealing element and a back pressure ring arranged on the low-pressure surface of the annular sealing element. In use, the back pressure ring is press-fitted to the inner surface of the outer casing component, and the annular sealing element makes pressurized contact with the back pressure ring. The present specification also discloses a method for mounting the sealing array in the turbomachine.

Inventors

• 디 시스토, 파올로
• 지우스티, 엔리코
• 카촐리, 잔루카
• 부차렐리, 페데리코
• 디우르노, 톰마소

Assignees

• 누보 피그노네 테크놀로지 에스알엘

Dates

Publication Date

20260511

Application Date

20240830

Priority Date

20230908

Claims (20)

1. As a turbo machine, External casing components; An inner casing component accommodated in the outer casing component and coupled to the outer casing component - the outer casing component has an inner surface facing the inner casing component -; A passage between the inner casing component and the outer casing component; An annular sealing element arranged in the above passage - the annular sealing element has a high-pressure surface and a low-pressure surface -; A turbomachine comprising a back pressure ring arranged on the low-pressure surface of the annular sealing element—when in use, the back pressure ring is press-fitted to the inner surface of the outer casing component, and the annular sealing element is in pressurized contact with the back pressure ring.
2. A turbomachine according to claim 1, wherein the back pressure ring is made of a material having a first thermal expansion coefficient, and the outer casing component is made of a material having a second thermal expansion coefficient, and the first thermal expansion coefficient is higher than the second expansion coefficient.
3. A turbomachine according to claim 1 or 2, wherein when the turbomachine is at room temperature, the back pressure ring has an outer diameter less than or equal to the inner diameter of the outer casing component at the axial position where the back pressure ring is arranged.
4. A turbomachine according to any one of claims 1 to 3, wherein the annular sealing element is a continuous monolithic element.
5. A turbomachine according to any one of claims 1 to 4, wherein the outer casing component is a barrel casing component.
6. A turbomachine according to any one of claims 1 to 5, wherein the back pressure ring is a continuous monolithic ring.
7. A turbomachine according to any one of claims 1 to 6, wherein the annular sealing element is planar.
8. A turbomachine according to any one of claims 1 to 6, wherein the annular sealing element is conical in the shape of a Belleville washer.
9. A turbomachine according to any one of claims 1 to 8, further comprising a holding device configured to prevent axial displacement of the back pressure ring.
10. In claim 9, the holding device comprises a shear ring arranged in an annular groove on the inner surface of the outer casing component and protruding radially inward from the annular groove; the shear ring contacts the back pressure ring on the surface of the back pressure ring opposite the annular sealing element, a turbomachine.
11. In Clause 10, the above shear ring is a monolithic turbomachine.
12. In paragraph 11, the above shear ring is elastically snap-coupled to the above annular groove, a turbomachine.
13. A turbomachine according to claim 10, wherein the shear ring comprises a plurality of shear ring segments arranged in the annular groove.
14. In paragraph 13, the above shear ring segments are mechanically coupled to the outer casing component by a plurality of fasteners, a turbomachine.
15. A turbomachine according to any one of claims 1 to 14, wherein the annular sealing element comprises a radially outer annular sealing region and a radially inner annular sealing region; the radially outer annular sealing region is in pressurized contact with the back pressure ring; and the radially inner annular sealing region is in pressurized contact with the radially extended annular pressure surface of the inner casing component.
16. A turbomachine according to claim 15, wherein the radial outer annular sealing region comprises a first annular ridge that protrudes toward the back pressure ring and makes pressurized contact with it.
17. In claim 16, the turbomachine having an externally curved and convex contact surface configured to make pressurized contact with the back pressure ring.
18. A turbomachine according to claim 15, 16 or 17, wherein the radial inner annular sealing region comprises a second annular ridge protruding toward the radially extended annular pressure surface of the inner casing component.
19. A turbomachine according to claim 18, wherein the second annular ridge has an externally curved and convex contact surface configured to make pressurized contact with the annular pressure surface of the inner casing component.
20. A turbomachine according to any one of claims 1 to 19, further comprising an elastic member arranged adjacent to the annular sealing element on a surface opposite to the back pressure ring and configured to bias the annular sealing element with respect to the back pressure ring.

Description

A turbomachine including a seal between an outer casing component and an inner casing component, and a method The subject matter disclosed herein relates to turbomachines and their components. In particular, the embodiments disclosed herein relate to a turbomachine comprising an outer casing, an inner casing, and a sealing arrangement between the inner casing and the outer casing, wherein the inner casing accommodates a fixed blade and a rotor of the turbomachine. Many conventional turbomachines, such as expanders and gas turbines, consist of an inner casing mounted on an outer casing. The inner casing is configured to thermally expand and contract radially and axially relative to the outer casing due to the temperature difference between the inner and outer casings. The outer casing is typically divided along a horizontal plane, that is, a plane containing the rotational axis of the turbomachine. A casing consisting of two matching parts along a plane containing the rotational axis of the turbomachine is referred to as a "horizontally split type." The two parts of the outer casing are bolted together along a flange. The gas stream flowing through the inner casing has a higher temperature than the gas stream passing through the annular space between the inner and outer casings. The different temperatures of the gas streams lead to different expansion rates for the inner and outer casings. The annular space provided between the inner casing and the outer casing is divided into two or more annular subspaces of different pressures, which are separated by an inner-outer casing sealing array. Due to the aforementioned different relative thermal expansion rates of the inner casing and the outer casing, the inner-outer casing sealing array must allow for axial and radial displacement of the inner and outer casings in the area of the seal passage where the sealing array is located. Unless otherwise indicated, as used herein, "axial" and "axially" mean parallel to the axis of rotation of the turbomachine; "radially"; and "radially" and "radially" mean perpendicular to the axis of rotation. Plate-type or membrane-type seals are provided for this purpose. When the outer casing is horizontally divided, the plate seal can be easily manufactured in the form of a continuous ring that is mounted on the other half of the outer casing before one half of the outer casing is mounted to surround and enclose the inner casing. Subsequently, the plate seal is received in a tangential groove machined in the two parts of the outer casing that are horizontally divided. Horizontal split-type outer casings may experience some limitations and disadvantages in high-pressure applications. In fact, when the gas inside the outer casing has a very high pressure of tens to hundreds of bar, the bolts connecting the two halves of the horizontal split-type casing may break and leakage may occur. Recently developed oxygen-fuel combustion cycles often operate with supercritical carbon dioxide ( sCO2 ) at pressures exceeding 50 bar, which can reach several hundred bar at the peak pressure point of the thermodynamic cycle. Horizontal split casings are not suitable for this type of turbomachine. The very high pressures associated with supercritical CO2 cycles necessitate the use of so-called barrel-type casings or vertical split casings. A vertical split casing comprises two casing components coupled by flanges and bolts along a plane orthogonal to the rotational axis of the turbomachine. In the forward section of the turbomachine, the outer casing component is monolithic, meaning it is a barrel-shaped structure with a continuous annular structure extending around the rotational axis of the turbomachine. The inner-outer casing sealing array, positioned in the annular space between the barrel-shaped outer casing component and the inner casing component, must be discontinuous in this case; that is, it must have radial interruptions to allow its mounting to the monolithic barrel-shaped outer casing component. Discontinuous annular seals are inefficient because the discontinuity of the annular seal causes gas leakage from the high-pressure region to the low-pressure region. An arrangement of this type of seal is disclosed, for example, in US2013/0104565. Improvements to internal-external sealing arrangements configured to mitigate the aforementioned disadvantages will be welcomed in this technical field. According to one aspect of an exemplary embodiment, the present specification discloses a turbomachine comprising an outer casing component and an inner casing component received in the outer casing component and coupled to the outer casing component. A passage is provided between the inner casing component and the outer casing component, and a sealing array is positioned in the passage. The sealing array comprises an annular sealing element and a back pressure ring arranged on the low-pressure surface of the annular sealing element. In use, the back pre