Continuous Acoustic Liner Assembly for Fan Flow Path Continuity

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Solution Overview

Problem

The structural segmentation of acoustic liners between the inlet case and fan case in gas turbine engines introduces flow path disturbances and challenges in acoustic treatment, leading to aerodynamic losses.

Innovation Solution

A continuous acoustic liner assembly is implemented, secured by a retaining ring and bonded to the fan case, with spacer shims and potting compound used to fill gaps, and a guide pin for alignment, reducing disturbances and enhancing acoustic treatment between the cases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If acoustic liners are segmented between inlet case and fan case, then assembly and installation become simpler, but flow path disturbances and aerodynamic losses increase

Engineering Contradiction:
Improveassembly simplicityVSAvoidflow path disturbances
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

A retaining ring serves as an intermediary component between the acoustic liner and fan case, providing a seamless connection that eliminates flow path disturbances while maintaining assembly simplicity. The retaining ring acts as a mediator that connects the segmented components without creating interruptions in the acoustic liner or flow path.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If acoustic liners are segmented between inlet case and fan case, then manufacturing and installation become easier, but acoustic treatment continuity is compromised

Engineering Contradiction:
Improveinstallation easeVSAvoidacoustic treatment continuity
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The retaining ring acts as an intermediary that bridges the gap between segmented acoustic liner sections, maintaining acoustic treatment continuity while allowing for easier manufacturing and installation of individual components. This mediator ensures that the acoustic properties remain consistent across the entire fan case interior surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-generated harmful factors

If acoustic liner is continuously treated between inlet case and fan case, then acoustic performance and aerodynamic efficiency improve, but assembly complexity increases

Engineering Contradiction:
Improvefan noise reductionVSAvoidassembly complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The acoustic liner system is segmented into modular sections that can be manufactured and installed separately, yet the retaining ring ensures continuous acoustic treatment. This segmentation allows for reduced fan noise through continuous acoustic coverage while keeping assembly manageable through standardized modular components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The retaining ring serves multiple functions simultaneously: it secures the acoustic liner in place, maintains structural integrity, ensures acoustic treatment continuity, and simplifies assembly procedures. This multi-functionality reduces overall assembly complexity while achieving continuous acoustic performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution reduces fan noise and airflow disruptions, improving aerodynamic efficiency by providing continuous acoustic treatment and secure assembly of the acoustic liner.

Implementation Method 1

a potting compound is disposed in the forward gap, to thereby fill the forward gap

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

a damper is bonded to the retaining ring groove and disposed between the retaining ring groove and the aft end of the acoustic liner

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 3

an acoustic liner extends between the inlet case and the fan case

Methodology Applied
Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentEP4163482B1Gas turbine engine with acoustic liner
Publication Date: 2025.11.26 RTX CORP
  • EP4163482B1 patent drawingFigure 1
  • EP4163482B1 patent drawingFigure 2
  • EP4163482B1 patent drawingFigure 3

AI summary

An assembly (100) for a gas turbine engine (20) has: a fan case (110) with a forward end (110A), an aft end (110B), and an inner surface (115) extending from the forward end (110A) of the fan case (110) to the aft end (110B) of the fan case (110); an acoustic liner (120) having a forward end (120A), an aft end (120B), and an acoustic liner body (125) that extends continuously from the forward end (120A) of the acoustic liner (120) to the aft end (120B) of the acoustic liner (120); an inlet case (130) located forward of the forward end (110A) of the fan case (110), the forward end of the acoustic liner (120) being secured to the inlet case (130), and wherein the acoustic liner body (125) is positioned against an inner surface (135) of the inlet case (130) and an inner surface (115) of the fan case (110), and the aft end (120B) of the acoustic liner (120) is secured to the fan case (110) between the forward end (110A) and the aft end (110B) of the fan case (110).