Dovetail TOBI Vane Mounting for Stress Reduction

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Solution Overview

Problem

The existing TOBI module in gas turbine engines faces wear and stress issues due to driving loads from the core flow, particularly at the mounting flanges of the TOBI vanes, which can lead to structural integrity concerns and require high-strength materials for durability.

Innovation Solution

The design incorporates a TOBI housing with a slot and dovetail configuration that allows for removability and better load distribution, along with a plenum and cooling passages to provide cooling fluid to the vanes, reducing stress and enabling the use of lower strength materials like molybdenum-silicon-boron alloy, and eliminates the need for fasteners between the inner flange and combustor housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional TOBI vane mounting flanges are used with fasteners, then structural strength can be maintained, but wear from rocking during operation occurs and assembly complexity increases

Engineering Contradiction:

Improvestructural integrityVSAvoidwear resistance

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces the traditional mechanical fastener system with a dovetail mechanical interlock system. The dovetail configuration uses geometric interlocking surfaces that prevent relative motion and eliminate the need for fasteners, while the broader bearing surface distributes loads to prevent wear during operational rocking.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If high-strength materials are used for TOBI vanes, then durability under driving loads is improved, but material cost and manufacturing complexity increase

Engineering Contradiction:

ImprovedurabilityVSAvoidmaterial cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The dovetail configuration provides built-in mechanical cushioning through its geometric design. The interlocking surfaces and broader bearing areas distribute and absorb driving loads before they can concentrate on the vane material, reducing peak stresses and enabling the use of lower-strength, more cost-effective materials.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Stability of the object's composition

If TOBI vanes are securely fastened to combustor housing, then structural stability is improved, but assembly complexity and fastener requirements increase

Engineering Contradiction:

Improvestructural stabilityVSAvoidassembly complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent merges the mounting flange function and the fastening function into a single integrated dovetail structure. The dovetail configuration itself provides both the structural connection and the secure locking mechanism, eliminating the need for separate fasteners and simplifying the overall assembly process.

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If cooling passages are added to TOBI vanes, then thermal stress is reduced, but manufacturing complexity increases

Engineering Contradiction:

Improvestress resistanceVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent incorporates cooling passages directly into the vane structure, creating a porous or channelled internal geometry that allows cooling fluid flow. This design enables thermal management to reduce thermal stresses while the passages are integrated into the manufacturing process, minimizing additional complexity.

Inventive Principle:

Principle #31Porous materials

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 enhances the durability and reduces stress on the TOBI vanes, allowing for the use of lower strength materials and simplifying assembly, while maintaining structural integrity and reducing wear, thus improving the overall performance and longevity of the gas turbine engine components.

Implementation Method 1

A cooling passage fluidly connects the plenum to the vane

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 2

provides cooling fluid to the vane, reducing stress

Methodology Applied

Scientific EffectThermal stress reduction:

Data Source

PatentUS11092025B2Gas turbine engine with dove-tailed TOBI vane

Publication Date: 2021.08.17 RTX CORP

AI summary

A combustor assembly for a gas turbine engine includes a TOBI module that includes a TOBI housing. The TOBI housing has a slot. A vane includes a dovetail removably received within the slot. The TOBI housing includes an axially extending TOBI nozzle array. The TOBI housing includes a plenum. A cooling passage fluidly connects the plenum to the vane. The TOBI housing includes passages configured to provide cooling fluid to the vane. The TOBI housing includes a first passageway further connecting the TOBI nozzle to the plenum.