Aft FLADE Engine Design for Variable Cycle Adaptation

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Solution Overview

Problem

FLADE engines face challenges with low pressure spool designs compromised by rotor speed limitations and increased stresses due to blade attachment and location, making it difficult and costly to adapt existing engines to incorporate front fan-mounted FLADE fans, and to demonstrate system benefits effectively.

Innovation Solution

The aft FLADE gas turbine engine design features a fan section connected to a low pressure turbine with a fan bypass duct and an aft FLADE turbine, allowing for uncompromised low pressure spool designs, easier adaptation to existing engines, and cost-effective demonstration of FLADE engine benefits, with features like variable vanes, power extraction apparatus, and thrust augmenting afterburners.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If front fan mounted FLADE fan blades are used, then the engine can achieve variable cycle capability, but the low pressure spool design is compromised due to rotor speed limitations and increased stresses

Engineering Contradiction:

Improvevariable cycle capabilityVSAvoidlow pressure spool design integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

Instead of mounting the FLADE fan blades on the front fan as in conventional designs, this patent inverts the arrangement by mounting the FLADE fan blades on an aft fan. This reversal of the mounting location eliminates the rotor speed limitations and increased stresses associated with front fan mounting, while still achieving variable cycle capability through the FLADE mechanism.

Inventive Principle:

Principle #13The other way round (Inversion)

2Adaptability or versatility

If front fan mounted FLADE fan blades are used, then the engine can operate as a variable cycle engine, but adaptation to existing engines becomes difficult and expensive

Engineering Contradiction:

Improvevariable cycle operationVSAvoidadaptation cost and difficulty

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent reverses the conventional FLADE fan blade mounting arrangement from front fan to aft fan. This inversion makes adaptation to existing engines easier and less expensive because the aft fan location provides better structural support, allows for simpler integration with the existing engine core, and avoids the complex modifications required for front fan mounting.

Inventive Principle:

Principle #13The other way round (Inversion)

3Adaptability or versatility

If a new low pressure system is designed around an existing core engine, then FLADE engine benefits can be demonstrated, but the cost and complexity increase significantly

Engineering Contradiction:

Improvedemonstration of FLADE benefitsVSAvoidsystem design complexity and cost

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of designing a completely new low pressure system around an existing core engine, the patent inverts the approach by integrating the FLADE mechanism with the existing low pressure system's aft fan. This inverted integration approach maintains the benefits of the FLADE engine while significantly reducing system complexity and cost by utilizing existing engine components and structures.

Inventive Principle:

Principle #13The other way round (Inversion)

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 allows for efficient operation across various flight conditions, maintains constant inlet airflow, reduces adaptation costs, and simplifies the integration of FLADE engines into existing systems, enhancing performance and reducing expenses.

Implementation Method 1

an aft FLADE turbine downstream of the mixer. At least one row of aft FLADE fan blades is disposed radially outwardly of and drivenly connected to the aft FLADE turbine

Methodology Applied

Scientific EffectTurbine: Turbine

Implementation Method 2

a fan section drivenly connected to a low pressure turbine section, a core engine located between the fan section and the low pressure turbine section, a fan bypass duct circumscribing the core engine and in fluid communication with the fan section

Methodology Applied

Scientific EffectFan: Fan

Data Source

PatentUS7216475B2Aft FLADE engine

Publication Date: 2007.05.15 GENERAL ELECTRIC CO

AI summary

An aft FLADE gas turbine engine includes a fan section drivenly connected to a low pressure turbine section, a core engine located between the fan section and the low pressure turbine section, a fan bypass duct circumscribing the core engine and in fluid communication with the fan section, and a mixer downstream of the low pressure turbine section and in fluid communication with the fan bypass duct, and an aft FLADE turbine downstream of the mixer. At least one row of aft FLADE fan blades disposed radially outwardly of and connected to the aft FLADE turbine and radially extending across a FLADE duct circumscribing the fan bypass duct. The aft FLADE turbine may be a free turbine or connected to and rotatable with the low pressure turbine section. A power extraction apparatus may be disposed within the engine and drivenly connected to the aft FLADE turbine.