Unitary Inner Diffuser Structure for Gas Turbine Windage Reduction

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Solution Overview

Problem

Gas turbine engines face significant aerothermal losses and heat pickup due to frictional interactions between rotating and static structures, leading to reduced component life and engine performance, as existing solutions like segmented sheet metal windage covers are incomplete and require tool access for disassembly.

Innovation Solution

A gas turbine engine design featuring a unitary inner diffuser structure with an annular combustor and tangential onboard injector inseparably attached, secured by fasteners with centerlines outside the diffuser gas flow path, reducing airflow perturbations and windage by minimizing features within the diffuser section.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If segmented sheet metal windage covers are used to shield rotating control volume, then ease of retrofitting is improved, but windage reduction is incomplete because tooling access is required for disassembly

Engineering Contradiction:

Improveease of retrofittingVSAvoidwindage

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The windage cover is divided into multiple segments that can be independently positioned and secured. Each segment contains fasteners with centerlines disposed outside the diffuser ID flow path, allowing the segments to be assembled without requiring tooling access through the flow path while maintaining complete shielding coverage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The fastener centerlines are positioned in a different spatial dimension (radially outside the diffuser ID flow path) rather than within it. This dimensional repositioning allows the fasteners to perform their securing function without intruding into the critical flow path area, thereby eliminating windage while maintaining ease of assembly.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Strength

If fasteners are used to secure components within the diffuser section, then structural integrity is improved, but aerothermal losses increase due to fastener-induced airflow perturbations

Engineering Contradiction:

Improvestructural integrityVSAvoidaerothermal losses

Core Design Contradiction:

StrengthVSLoss of energy

Solution Approach 1:

The fastener centerlines are strategically positioned in specific locations (outside the diffuser ID flow path) where they can perform their structural securing function without creating harmful airflow perturbations. This localized quality differentiation ensures that the fasteners provide structural integrity while minimizing their negative impact on aerothermal performance.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If multiple discrete components are assembled within the diffuser section, then adaptability is improved, but device complexity increases leading to more windage sources

Engineering Contradiction:

Improvecomponent configuration flexibilityVSAvoidnumber of features

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple discrete components (inner diffuser case, combustor, TOBI, and windage cover segments) are integrated into a coordinated assembly where the windage cover segments are inseparably attached to the diffuser components. This merging reduces the number of separate features and interfaces within the flow path, thereby reducing windage sources while maintaining the adaptability of the overall component configuration.

Inventive Principle:

Principle #5Merging (Combining)

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 design effectively mitigates windage and aerothermal losses by eliminating fastener-induced airflow perturbations, enhancing component life and engine performance while facilitating easier assembly.

Implementation Method 1

heat addition due to frictional losses

Methodology Applied

Scientific EffectFrictional losses: Friction

Implementation Method 2

rotational pumping of the cooling air against static structures

Methodology Applied

Scientific EffectRotational pumping: Pump

Data Source

PatentUS20240353105A1Gas turbine engine configured for decreased diffuser windage and method of assembling the same

Publication Date: 2024.10.24 RTX CORP

AI summary

A gas turbine engine is provided having an axial centerline, a compressor section, a turbine section, and a combustor section. The turbine section has a turbine first vane assembly that includes an annular first vane inner radial support. The combustor section has an outer casing, an annular combustor, and a unitary inner diffuser structure. The annular combustor has an inner radial flange. The unitary inner diffuser structure includes a compressor discharge, an inner diffuser case, and a tangential onboard injector (TOBI) inseparably attached to one another. The unitary inner diffuser structure further includes an outer radial flange and a TOBI connection flange. The annular FV inner radial support, the combustor inner radial flange, and the TOBI connection flange are secured to one another.