Gas Turbine Blade Dovetail Flared Slot Design

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing blade dovetail and fan hub slot designs in gas turbine engines experience stress concentrations at their ends due to high load transfer, leading to mechanical deformation and potential failure.

Innovation Solution

The design incorporates flared ends for the fan hub slot and shaved ends for the blade dovetail, allowing for extended contact areas during deformation, thereby distributing loads more evenly and reducing stress concentrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the blade dovetail and fan hub slot are designed with conventional straight edges, then the assembly is simple to manufacture, but stress concentrations occur at the ends due to high load transfer

Engineering Contradiction:
Improvestress concentration reductionVSAvoidslot and dovetail geometry
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies local quality by modifying only the end regions of the slot and dovetail with curved geometries, while the central portions remain straight. This localized modification reduces stress concentrations at the critical end areas without unnecessarily complicating the entire structure, thereby improving strength where needed while maintaining manufacturing simplicity elsewhere.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements curvature by replacing the conventional straight edges of the slot and dovetail with curved geometries at their ends. This spheroidality principle smooths the stress distribution by eliminating sharp corners and abrupt transitions, reducing stress concentrations and preventing mechanical deformation while maintaining overall structural integrity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Area of stationary object

If the slot and dovetail have straight edges, then the manufacturing process is simple, but the contact area during deformation is limited

Engineering Contradiction:
Improvecontact areaVSAvoidslot and dovetail fabrication
Core Design Contradiction:
Area of stationary objectVSEase of manufacture

Solution Approach 1:

By curving the ends of the slot and dovetail, the patent increases the effective contact area during blade deformation. The curved geometry allows for a more gradual engagement and larger surface area in contact compared to straight edges, improving load distribution while the curvature can still be achieved through standard machining operations.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameters of the slot and dovetail from straight to curved at the ends. This parameter modification increases the contact area and improves the deformation characteristics without fundamentally changing the manufacturing process, as the curved geometry can be produced using conventional machining techniques.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional straight-edged dovetails and slots are used, then assembly is straightforward, but mechanical deformation occurs at high rotational speeds

Engineering Contradiction:
Improvemechanical integrityVSAvoidcurved geometry configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by implementing curved geometries only at the end regions of the slot and dovetail, where stress concentrations occur during high-speed rotation. The central portions remain straight to maintain structural integrity and simplicity. This localized approach improves reliability at critical stress points without unnecessarily complicating the overall assembly.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The curved geometries at the ends of the slot and dovetail prevent mechanical deformation during high-speed rotation by distributing centrifugal forces more evenly. The curvature allows for gradual engagement and reduces stress concentrations that would otherwise lead to deformation or failure, thereby improving mechanical integrity while maintaining straightforward assembly procedures.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

This configuration effectively reduces stress concentrations at the ends of the fan hub slots and blade dovetails, enhancing the mechanical integrity and operational reliability of gas turbine engines.

Implementation Method 1

as the rotor rotates at increasingly higher speeds, the blade dovetail begins to mechanically deform due to centrifugal forces

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3789586B1Aerodynamic element assembly for a gas turbine engine
Publication Date: 2025.04.16 RTX CORP
  • EP3789586B1 patent drawingFigure 1
  • EP3789586B1 patent drawingFigure 2~3
  • EP3789586B1 patent drawingFigure 4~5

AI summary

An aerodynamic element assembly (201) is provided and includes a hub (210) defining a slot (212) and an aerodynamic element (220). The aerodynamic element (220) includes a dovetail section (221) receivable in the slot (212) and an airfoil section (222) configured to aerodynamically interact with fluid to drive hub and aerodynamic element rotations around a rotational axis. The dovetail section (221) is deformable during operational conditions from an initial configuration to a deformed configuration and, with the dovetail section (221) assuming the initial configuration, at least one of ends (2120) of the slot (212) are flared and thereby configured to be spaced apart from corresponding ends (2210) of the dovetail section (221) and ends (2210) of the dovetail section (221) are shaved and thereby configured to be spaced apart from corresponding ends (2120) of the slot.