Open rotor with aerodynamically isolatable free turbine

Patent metadata

Field	Value
Publication number	US-2026015968-A1
Application number	US-202418773118-A
Country	US
Kind code	A1
Filing date	Jul 15, 2024
Priority date	Jul 15, 2024
Publication date	Jan 15, 2026
Grant date	—

Abstract

An assembly for an aircraft propulsion system includes an open propulsor rotor driven by a power turbine section disposed in the engine core. A power turbine isolation system disposed between an LP turbine section and the power turbine section includes a transition duct therebetween and a flow diverter. The flow diverter is selectively configured to direct engine core flow into the power turbine section to drive the propulsor rotor in one mode (normal operation/mode), and block the engine core flow into the power turbine section and divert the flow through a bypass path in a second mode (bypass operation/mode). In the bypass mode, the power turbine is undriven which effectively prevents or substantially reduces rotation of the propulsor rotor. This reduces or eliminates safety risks to ground crews resulting from an open propulsor rotor actively rotating as the aircraft is on the ground.

First claim

What is claimed is:

1 . An aircraft propulsion system, comprising:
a core engine defining an engine airflow path, the core engine comprising a first spool section having a first compressor, a first turbine and a first spool shaft coupled to the first compressor and the first turbine;
a power turbine assembly disposed downstream of the first turbine, the power turbine assembly comprising a power turbine coupled to a power turbine shaft;
an open propulsor rotor disposed upstream of the power turbine assembly and coupled to the power turbine shaft, the open propulsor rotor comprising a plurality of rotor blades;
a power turbine isolation system disposed between the first turbine and the power turbine, the power turbine isolation system comprising, a transition duct configured to receive an engine airflow from the first turbine, and a flow diverter comprising a plurality of blocking doors selectively configured to, in a first mode close each of the plurality of blocking doors to cause engine airflow to flow into the power turbine and drive the open propulsor rotor via the power turbine shaft; and in a second mode open each of the plurality of blocking doors to restrict the engine airflow from flowing into the power turbine and cease driving the open propulsor rotor via the power turbine shaft.

2 . The aircraft propulsion system in accordance with claim 1 , wherein the flow diverter is configured to, in the first mode, direct the engine airflow to the power turbine and block the engine airflow from flowing into a bypass airflow path.

3 . The aircraft propulsion system in accordance with claim 1 , wherein the flow diverter is further configured to, in the second mode, direct the engine airflow into a bypass airflow path and prevent the engine airflow from flowing into the power turbine.

4 . The aircraft propulsion system in accordance with claim 1 , wherein the flow diverter is configured as a blocker door and selectively movable into a first position associated with the first mode and a second position associated with the second mode.

5 . (canceled)

6 . The aircraft propulsion system in accordance with claim 1 , wherein the core engine further comprises:
a second spool section having a second compressor, a second turbine disposed upstream of the power turbine assembly, and a second spool shaft coupled to the second compressor and the second turbine.

7 . The aircraft propulsion system in accordance with claim 1 , wherein the power turbine isolation system further comprises:
one or more extension ducts configured to receive the engine airflow in the second mode and direct the engine airflow outside the engine.

8 . The aircraft propulsion system in accordance with claim 1 , further comprising:
a brake mechanism selectively configured to inhibit rotation of the open propulsor rotor in the second mode.

9 . The aircraft propulsion system in accordance with claim 8 , wherein the brake mechanism is configured to be operable only when the aircraft propulsion system is on the ground.

10 . (Withdrawn-Currently Amended) An aircraft propulsion system, comprising:
a core engine defining an engine airflow path, the core engine comprising: a first spool section having a first compressor, a combustion section, a first turbine and a first spool shaft coupled to the first compressor and the first turbine,and a second spool section having a second compressor, a second turbine and a second spool shaft coupled to the second compressor and the second turbine;
a power turbine assembly disposed downstream of the second turbine, the power turbine assembly comprising a power turbine coupled to a power turbine shaft;
an open propulsor rotor disposed upstream of the power turbine assembly and coupled to the power turbine shaft, the open propulsor rotor comprising a plurality of rotor blades; and
an engine airflow diverter disposed between the second turbine and the power turbine comprising a plurality of blocking doors, the engine airflow diverter selectively configured to, in a first mode close each of the plurality of blocking doors to cause engine airflow to flow into the power turbine and drive the open propulsor rotor via the power turbine shaft; and in a second mode open each of the plurality of blocking doors to restrict the engine airflow from flowing into the power turbine and cease driving the open propulsor rotor via the power turbine shaft.

11 . The aircraft propulsion system in accordance with claim 10 , wherein the engine airflow diverter is configured to, in the first mode, direct the engine airflow to the power turbine and block the engine airflow from flowing into a bypass airflow path.

12 . The aircraft propulsion system in accordance with claim 10 , wherein the engine airflow diverter is further configured to, in the second mode, direct the engine airflow into the bypass airflow path and prevent the engine airflow from flowing into the power turbine.

13 . The aircraft propulsion system in accordance with claim 10 , wherein the engine airflow diverter is configured as a blocker door and selectively movable into a first position associated with the first mode and a second position associated with the second mode.

14 . (canceled)

15 . The aircraft propulsion system in accordance with claim 10 , wherein the engine airflow diverter further comprises:
one or more extension ducts configured to receive the engine airflow and direct the engine airflow outside the aircraft propulsion system.

16 . The aircraft propulsion system in accordance with claim 10 , further comprising:
a brake mechanism selectively configured to inhibit rotation of the open propulsor rotor in the second mode.

17 . The aircraft propulsion system in accordance with claim 16 , wherein an operation of the brake mechanism is limited to when the aircraft propulsion system is on the ground.

18 . (Withdrawn-Currently Amended) An open rotor engine, comprising:
a transition duct disposed between a first turbine and a power turbine and configured to receive an engine airflow from the first turbine; and a flow diverter disposed within the transition duct comprising a plurality of blocking doors and configured to: cause engine airflow from the first turbine to flow into the power turbine when the plurality of blocking doors are each closed in a first position, and restrict the engine airflow from flowing into the power turbine and cause the engine airflow to flow through another path when the plurality of blocking doors are each open in a second position.

19 . The open rotor engine in accordance with claim 18 , further comprising:
a power turbine shaft coupled to the power turbine; and an open propulsor rotor disposed near one end of the engine and coupled to the power turbine shaft, the open propulsor rotor comprising a plurality of rotor blades.

20 . The open rotor engine in accordance with claim 19 , further comprising:
a brake mechanism selectively configured to inhibit rotation of the open propulsor rotor when the flow diverter is in the second position.

Assignees

• Rtx Corp

Inventors

• Morton Jeffrey T
• Sobanski Jon E
• Breault Andrew E
• Hanrahan Paul R

Classifications

• F02K3/075

  controlling flow ratio between flows · CPC title

• F02K3/06

  with front fan · CPC title

• F02C3/13

  having variable working fluid interconnections between turbines or compressors or stages of different rotors {(controlling flow ratio between different flows of multi-flow jet-propulsion plant, e.g. ducted fan F02K3/075)} · CPC title

• F02C3/10 Primary

  with another turbine driving an output shaft but not driving the compressor · CPC title