Aft Core Driven Fan Section for Gas Turbine Engine

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Solution Overview

Problem

Gas turbine engines face challenges in achieving high specific thrust and low fuel consumption across varying operating conditions, as existing technologies struggle to efficiently manage airflow and pressure ratios to optimize performance and efficiency.

Innovation Solution

The implementation of a reverse-flow core gas turbine engine with an aft core driven fan section and a variable area third stream exhaust nozzle, allowing for control of the aft inlet guide vane and nozzle throat to adjust airflow and pressure ratios dynamically, enabling efficient thrust generation and fuel optimization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a variable cycle engine alters bypass ratio to match varying requirements, then specific thrust is improved during high-power maneuvers, but fuel consumption increases during cruise conditions

Engineering Contradiction:

Improvespecific thrustVSAvoidfuel consumption

Core Design Contradiction:

ForceVSUse of energy by moving object

Solution Approach 1:

The engine implements dynamic control of the bypass ratio through variable area nozzles and adjustable guide vanes, allowing the third stream airflow to be modulated in real-time. This enables the engine to optimize the balance between specific thrust and fuel consumption by adjusting the bypass ratio according to flight conditions, resolving the contradiction between high thrust performance and fuel efficiency

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The engine changes the airflow parameters by controlling the variable area throat of the third stream exhaust nozzle and the aft inlet guide vane angle. By varying these parameters, the engine can adjust the bypass ratio to achieve high specific thrust when needed while maintaining fuel efficiency during cruise, effectively managing the trade-off between thrust and fuel consumption

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If an aft core driven fan section is added to control airflow dynamically, then engine performance across varying conditions is improved, but device complexity increases

Engineering Contradiction:

Improveengine performance across operating conditionsVSAvoidengine structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The aft core driven fan section serves multiple functions: it drives the third stream airflow, controls the bypass ratio, and contributes to thrust generation. By integrating these functions into a single component system, the engine achieves high adaptability across varying operating conditions without proportionally increasing complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the fan drive mechanism with the exhaust nozzle system, where the aft core driven fan section is integrated with the variable area third stream exhaust nozzle. This merging of functions allows dynamic airflow control while reducing the number of separate components, thereby improving adaptability without excessive complexity increase

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentEP2551485B1Gas turbine engine with aft core driven fan section

Publication Date: 2019.01.09 UNITED TECH CORP

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AI summary

A gas turbine engine (20) includes a low spool (3 8) along an engine axis with a forward fan section (22) and a low pressure turbine section (30). A high spool (40) along the engine axis has a high pressure turbine section (28) and an aft core driven fan section (32), the aft core driven fan section (32) axially aft of the high pressure turbine section (28) along the engine axis.