Aircraft Engine Diffuser Lug-Slot Mounting for Low-Leakage Flow Control

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Solution Overview

Problem

Existing vane diffusers in aircraft engines face challenges in efficiently orienting the flow from a centrifugal compressor to downstream components due to thermal distortions, leading to increased tip clearance and impaired performance.

Innovation Solution

A compressor assembly with a diffuser featuring an annular member and vanes secured to a bearing housing via lug and slot connections, eliminating the need for bolts and utilizing braze or weld joints, which reduces weight and leakage while maintaining structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional bolted connections are used to secure the diffuser to the bearing housing, then structural integrity is maintained, but weight increases and leakage risk increases

Engineering Contradiction:

Improvestructural integrityVSAvoiddiffuser assembly weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent replaces traditional mechanical bolted connections with a friction-based clamp system. The clamp applies radial force to press the diffuser against the bearing housing, creating friction that secures the diffuser without requiring bolts. This substitution eliminates the weight of multiple bolts and fasteners while maintaining structural integrity through friction forces.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the connection mechanism from rigid mechanical fastening to flexible friction-based clamping. By adjusting the clamp force parameter, the system can achieve adequate structural integrity without the weight penalty of traditional bolted connections. The friction parameter becomes the key design variable instead of bolt torque.

Inventive Principle:

Principle #35Parameter changes

2Strength

If traditional bolted connections are used to secure the diffuser to the bearing housing, then structural integrity is maintained, but leakage risk increases

Engineering Contradiction:

Improvestructural integrityVSAvoidleakage

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The friction-based clamp system creates uniform pressure distribution across the diffuser-bearing housing interface, improving sealing compared to discrete bolted connections. The continuous friction contact prevents leakage paths that can occur between bolt holes and flange surfaces in traditional bolted assemblies.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If thermal distortions are allowed to occur in the diffuser, then ease of manufacture is improved, but flow orientation performance deteriorates

Engineering Contradiction:

Improvediffuser manufacturingVSAvoidflow orientation efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent uses friction-based clamping to apply controlled thermal and mechanical parameters to the diffuser. The clamp force and contact pressure are adjusted to manage thermal distortions during operation, maintaining flow orientation performance while allowing manufacturing flexibility. The friction interface acts as a thermal management mechanism.

Inventive Principle:

Principle #35Parameter changes

4Weight of moving object

If the diffuser design is simplified to reduce weight, then weight decreases, but structural stability may be compromised

Engineering Contradiction:

Improvediffuser assembly weightVSAvoidstructural stability

Core Design Contradiction:

Weight of moving objectVSStability of the object's composition

Solution Approach 1:

The friction-based clamp system provides structural stability through distributed friction forces rather than discrete mechanical fasteners. The continuous contact surface creates stable load paths that maintain structural integrity while eliminating the weight of multiple bolts, nuts, and washers required in traditional designs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enhances flow orientation and reduces weight, improves structural stability, and minimizes leakage, thereby improving the overall performance and efficiency of the aircraft engine.

Implementation Method 1

the lug and slot connections comprise braze or weld joints within gaps extending around the lugs

Methodology Applied

Scientific EffectBrazing: Brazing

Implementation Method 2

the lug and slot connections comprise braze or weld joints within gaps extending around the lugs

Methodology Applied

Scientific EffectWelding: Welding

Data Source

PatentUS12467473B1Aircraft engine including diffuser secured to a bearing housing

Publication Date: 2025.11.11 PRATT & WHITNEY CANADA CORP

AI summary

A compressor assembly has: an impeller rotatable about a central axis, the impeller mounted on a shaft; a bearing housing extending around the central axis and radially supporting the shaft; and a diffuser downstream of the impeller, the diffuser having: an annular member extending circumferentially around the central axis, vanes circumferentially distributed around the central axis and protruding from one of the annular member and the bearing housing, the vanes extending from bases at the one of the annular member and the bearing housing to tips at the other of the annular member and the bearing housing, and lug and slot connections defined between the annular member and the bearing housing to secure the annular member to the bearing housing.