# US 12,006,846 B2 · Additively manufactured intermediate duct for disposition between a low-pressure compressor and a high-pressure compressor, and corresponding manufacturing method

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 12,006,846 B2
- Document ID: US12006846B2
- Status: Granted
- Kind: B2
- Application number: 16/759,489
- Filed: 2018-10-31
- Published: 2023-06-29
- Granted: 2024-06-11
- Earliest claimed: 2017-11-02
- Assignees: MTU Aero Engines AG
- Applicants: MTU Aero Engines AG
- Inventors: Ralf Homburg; Harsimar Sahota
- Web page: https://patentgrep.com/patent/US12006846B2

## CPC

- F01D 9/065: {Fluid supply or removal conduits traversing the working fluid flow, e.g. for lubrication-, cooling-, or sealing fluids (see also F01D25/16, F01D25/24 and F01D25/26)}
- F04D 29/542: {Bladed diffusers (fixing blades to stators F01D9/042)}
- F01D 9/041: {using blades (F01D5/148 takes precedence)}
- F04D 29/023: {especially adapted for elastic fluid pumps}
- F04D 29/544: {Blade shapes}
- F04D 29/545: {Ducts}
- F05D 2230/00: Manufacture
- F05D 2230/22: by sintering
- F05D 2230/31: Layer deposition
- F05D 2240/122: related to the trailing edge of a stator vane
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

An intermediate duct (10) for disposition between an outlet of a low-pressure compressor and an inlet of a high-pressure compressor of a turbomachine, in particular of an aircraft engine is provided, the intermediate duct including an outer wall (2) and an inner wall (3) between which are disposed an optional exit stator ring (4) and at least one strut (12) extending radially with respect to a central axis of the intermediate duct (10). The intermediate duct (10) is at least partially manufactured by additive manufacturing. A method for manufacturing such an intermediate duct (10), and a turbomachine having such an intermediate duct (10) are also provided.

## Claims

### Claim 1

An intermediate duct for disposition between an outlet of a low-pressure compressor and an inlet of a high-pressure compressor of a turbomachine, the intermediate duct comprising:
an outer wall;
an inner wall;
at least strut disposed between the outer wall and the inner wall and extending radially with respect to a central axis of the intermediate duct;
the intermediate duct at least partially manufactured by additive manufacturing;
the strut having a surface with a curvature with respect to a plane defined by the radial and axial directions so as to define an out-of-plane curvature in the circumferential direction;
wherein a radial shape of the at least one strut lies within a first boundary contour and a second boundary contour, at least in the region of a trailing edge, the first boundary contour being defined by the formula (I):
y=71.14x5−179.74x4+134.76x3−2.6539x2−27.72x+5.5815 (I)
and the second boundary contour being defined by the formula (II):
y=71.14x5−179.74x4+134.76x3−2.6539x2−27.72x+1.5815 (II),
where x denotes the percentage of the radial height of the strut from the inner wall of the intermediate duct in the region of its trailing edge, and y denotes the deviation, in degrees, in the circumferential direction from a hypothetical linear trailing edge contour having a constant radial shape at 0°.

### Claim 2 (depends on 1)

The intermediate duct as recited in claim 1 wherein the intermediate duct is composed of at least two connected segments.

### Claim 3 (depends on 1)

The intermediate duct as recited in claim 1 wherein the outer wall or the inner wall or the at least one strut or an exit stator ring disposed between the outer wall and the inner wall include at least one cavity.

### Claim 4 (depends on 3)

The intermediate duct as recited in claim 3 wherein the at least one cavity is configured as an open cavity or the at least one cavity is round or oval in cross section or at least two cross sections of the at least one cavity are staggered relative to each other or the at least one cavity has at least one constriction or the cavity is supported by at least one supporting strut.

### Claim 5 (depends on 3)

The intermediate duct as recited in claim 3 wherein the at least one cavity is configured a closed cavity or the at least one cavity is round or oval in cross section or at least two cross sections of the at least one cavity are staggered relative to each other or the at least one cavity has at least one constriction or the cavity is supported by at least one supporting strut.

### Claim 6 (depends on 3)

The intermediate duct as recited in claim 3 wherein the outer wall or the inner wall or the at least one strut or an exit stator ring disposed between the outer wall and the inner wall include at least one cavity or at least one supporting strut supporting the cavity have a bionic design.

### Claim 7 (depends on 1)

The intermediate duct as recited in claim 1 wherein the at least one strut includes a cavity forming a channel having an inlet port and an outlet port and allowing an operating fluid to be passed therethrough through the intermediate duct.

### Claim 8 (depends on 7)

The intermediate duct as recited in claim 7 wherein a fill factor of the at least one strut is between 15% and 95%.

### Claim 9 (depends on 8)

The intermediate duct as recited in claim 8 wherein the fill factor is between 50% and 90%.

### Claim 10 (depends on 1)

The intermediate duct as recited in claim 1 wherein a thickness ratio of a maximum thickness to an axial length of the at least one strut is between 15% and 45%.

### Claim 11 (depends on 1)

The intermediate duct as recited in claim 1 wherein a radial shape of a trailing edge of the at least one strut has a deviation of no more than ±7° in the circumferential direction, considered with respect to a round angle.

### Claim 12 (depends on 1)

The intermediate duct as recited in claim 1 further comprising an exit stator ring extending radially with respect to a central axis of the intermediate duct.

### Claim 13 (depends on 1)

The intermediate duct as recited in claim 1 wherein the intermediate duct is made from a titanium alloy or from a nickel-based alloy.

### Claim 14 (depends on 13)

The intermediate duct as recited in claim 13 wherein the intermediate duct is made from titanium 6246 or from IN100.

### Claim 15 (depends on 1)

A method for manufacturing the intermediate duct as recited in claim 1 to be disposed between an outlet of a low-pressure compressor and an inlet of a high-pressure compressor of a turbomachine, the intermediate duct including an outer wall and an inner wall between which is disposed an at least one strut extending radially with respect to a central axis of the intermediate duct, the method comprising: manufacturing at least part of the intermediate duct by additive manufacturing.

### Claim 16 (depends on 15)

The method as recited in claim 15 wherein the outer wall or the inner wall or the at least one strut or an exit stator ring disposed between the outer wall and the inner wall include at least one cavity or at least one supporting strut supporting the cavity are manufactured with at least one cavity or with a bionic design.

### Claim 17 (depends on 1)

A turbomachine comprising:
at least a low-pressure compressor and a high-pressure compressor;
an intermediate duct disposed between an outlet of the low-pressure compressor and an inlet of the high-pressure compressor, the intermediate duct being as recited in claim 1.

### Claim 18 (depends on 17)

An aircraft engine comprising the turbomachine as recited in claim 17.

### Claim 19 (depends on 1)

The intermediate duct as recited in claim 1 wherein the trailing edge of the strut is curved in the radial direction.