Hollow Fan Blade Check Valve for Argon Pressure Relief

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Solution Overview

Problem

Hollow fan blades for gas turbine engines face surface deformations due to trapped argon gas expanding during high-temperature stress relief and creep forming processes, leading to bulging issues.

Innovation Solution

Incorporating a check valve in a conduit extending from the cavity to the exterior surface of the fan blade, allowing a metered flow of gas to escape, which includes a spring-biased metering element and a valve seat to regulate pressure and prevent deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the cover is welded to the airfoil to enclose the cavity, then the structural integrity is improved, but trapped argon gas causes surface deformations during post-welding processing

Engineering Contradiction:
Improvestructural integrityVSAvoidsurface deformation
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

A conduit is formed in the airfoil during the molding process, and a check valve is installed in the conduit before the cover is welded to the airfoil. This preliminary setup allows trapped argon gas to escape during subsequent stress relief and creep forming operations, preventing surface deformations while maintaining the enclosed cavity structure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The check valve acts as an intermediary component that selectively allows argon gas to escape from the cavity through the conduit while preventing external contamination from entering. The valve opens under pressure differential during heating operations and closes when pressure equalizes, mediating between the need for gas release and cavity protection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If argon gas is allowed to escape from the cavity, then surface deformations are prevented, but external contamination may enter the cavity

Engineering Contradiction:
Improvesurface deformationVSAvoidexternal contamination
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The check valve is designed to convert the harmful effect of potential contamination into a beneficial selective flow system. The valve only opens when internal pressure exceeds external pressure (during heating operations), allowing trapped argon gas to escape while preventing external contamination from entering during normal conditions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The check valve operates based on pressure differential feedback between the internal cavity and external environment. When internal pressure rises during stress relief or creep forming operations, the valve opens to release gas. When pressure equalizes or drops, the valve closes to prevent contamination, creating a self-regulating system.

Inventive Principle:
Principle #23Feedback

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 check valve effectively relieves internal pressure, minimizing material deformations and maintaining structural integrity by allowing controlled gas release, while also preventing external contamination of the internal cavity.

Implementation Method 1

The check valve may include a spring biased metering element and a valve seat that limits movement of the metering element into the cavity

Methodology Applied
Scientific EffectSpring biasing: Spring

Implementation Method 2

the check valve configured to regulate an internal pressure of the cavity when the cover is secured to the airfoil

Methodology Applied
Scientific EffectPressure differential control: Pressure Gradient

Data Source

PatentEP3926142B1Fan blade for a gas turbine engine, gas turbine engine and method of forming a fan blade.
Publication Date: 2024.01.31 RTX CORP
  • EP3926142B1 patent drawingFigure 1
  • EP3926142B1 patent drawingFigure 2~3
  • EP3926142B1 patent drawingFigure 4~6

AI summary

Disclosed is a fan blade (100) for a gas turbine engine (20), including: an airfoil (115), a cavity (120) formed in the airfoil, a cover (125) configured to cover the cavity, the cover when secured to the airfoil encloses the cavity in the airfoil, a conduit (130) extending from the cavity to an exterior surface of the fan blade, and a check valve located in the conduit, the check valve (135) configured to regulate an internal pressure of the cavity when the cover is secured to the airfoil.