Segregated Core and Bypass Flow Lift Generation

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Solution Overview

Problem

VTOL aircraft using higher-energy gas turbine engines with low bypass ratios suffer from high specific fuel consumption during cruise flights and engine efficiency reduction due to disrupted exhaust flowfields, and the high temperatures from lift generation can damage surfaces and cause fires.

Innovation Solution

A method and apparatus that segregate core and bypass flows from a gas turbine engine, directing them in separate directions to generate lift without mixing, using a core duct and bypass duct to drive a lift fan and direct bypass flow, respectively, maintaining a bypass ratio of at least four to one and ensuring exit temperatures below 800°F.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If higher-energy gas turbine engines with low bypass ratios are used, then VTOL capability is achieved, but specific fuel consumption during cruise increases

Engineering Contradiction:

ImproveVTOL capabilityVSAvoidspecific fuel consumption

Core Design Contradiction:

PowerVSUse of energy by moving object

Solution Approach 1:

The exhaust flow is segmented into core flow and bypass flow streams, with the bypass flow directed through a dedicated bypass duct to generate lift separately from the core engine flow. This segmentation allows the engine to operate at optimal cruise conditions while using bypass flow for lift generation, reducing specific fuel consumption during cruise portions of flight.

Inventive Principle:

Principle #1Segmentation

2Force

If a shaft coupled to a turbine within the engine is used to drive the lift fan, then lift generation is achieved, but engine efficiency decreases due to disrupted exhaust flowfield

Engineering Contradiction:

Improvelift generationVSAvoidengine efficiency

Core Design Contradiction:

ForceVSLoss of energy

Solution Approach 1:

The lift generation function is extracted from the core engine turbine shaft system and implemented separately using diverted bypass flow. The bypass flow is directed through a bypass duct to drive the lift fan, eliminating the need for a shaft coupled to an internal turbine and preventing disruption of the engine's exhaust flowfield, thereby maintaining engine efficiency.

Inventive Principle:

Principle #2Taking out (Extraction)

3Force

If high temperature exhaust gases are used to generate lift, then lift generation is achieved, but surface damage and fire hazards occur

Engineering Contradiction:

Improvelift generationVSAvoidsurface damage and fire hazards

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The bypass duct serves as an intermediary channel that separates the high-temperature core flow from the lift generation process. By directing bypass flow through the bypass duct, the system achieves lift generation while the core flow's high temperature is isolated, preventing direct contact with surfaces and eliminating fire hazards on runways and terrain.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach decreases specific fuel consumption, reduces surface damage during takeoff and landing, and allows operation on various surfaces and in environments previously inaccessible due to high temperatures, while maintaining engine efficiency by not disrupting the exhaust flowfield.

Implementation Method 1

a gas turbine engine having a combustor, a core flow heated by the combustor, and a bypass flow which bypasses the combustor

Methodology Applied

Scientific EffectGas turbine engine operation: Turbine

Implementation Method 2

a core flow heated by the combustor

Methodology Applied

Scientific EffectCombustion heating: Combustion

Implementation Method 3

An end of the core duct downstream from the engine compartment is positioned with respect to the frame to direct the core flow received from the engine in a first direction to drive a lift fan without mixing the core flow received from the engine with bypass flow

Methodology Applied

Scientific EffectFluid flow direction control:

Implementation Method 4

An end of the bypass duct downstream from the engine compartment is positioned with respect to the frame to direct the bypass flow received from the engine in a second direction to generate lift for the vehicle without mixing the bypass flow with core flow

Methodology Applied

Scientific EffectFluid flow direction control:

Implementation Method 5

directing the segregated portion of the core flow in a first direction to generate lift for the vehicle

Methodology Applied

Scientific EffectLift generation: Aerofoil

Data Source

PatentUS7510140B2Method and apparatus for generating lift

Publication Date: 2009.03.31 THE BOEING CO

AI summary

A method of generating lift for a vehicle including a gas turbine engine having a combustor, a core flow heated by the combustor, and a bypass flow which bypasses the combustor. The method includes segregating at least a portion of the core flow from the bypass flow, directing the segregated portion of the core flow in a first direction to generate lift for the vehicle, segregating at least a portion of the bypass flow from the core flow, and directing the segregated a portion of the bypass flow in a second direction to generate lift for the vehicle.