Jet Nozzle Area Control Using Inflatable Diaphragms

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Solution Overview

Problem

Existing jet nozzle effective area adjustment mechanisms in gas turbine engines are bulky, heavy, and costly due to the use of multiple actuators, segmented panels, and mechanical arms, which increase the engine's size and weight.

Innovation Solution

Aircraft gas turbine engines employ inflatable diaphragms and hinged panels controlled by fluid pressure adjustments to adjust the effective area of the jet nozzle, reducing mechanical complexity and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple actuators, segmented panels, and mechanical arms are used to adjust jet nozzle effective area, then the jet nozzle effective area can be adjusted, but the size, weight, and expense of the engine increase

Engineering Contradiction:
Improvejet nozzle effective area adjustment capabilityVSAvoidengine weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The patent replaces traditional mechanical actuation systems (actuators, mechanical arms, pivot joints) with an inflatable diaphragm system that uses fluid pressure to achieve the same function of adjusting jet nozzle effective area. This substitution eliminates complex mechanical linkages and reduces overall system weight while maintaining the capability to vary nozzle area.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs an inflatable diaphragm system that uses fluid pressure (pneumatics) to control the deployment and retraction of panels that adjust the jet nozzle effective area. This pneumatic approach replaces heavy mechanical actuators with a lighter, more compact fluid pressure-based system that achieves the same adaptability function.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Adaptability or versatility

If multiple actuators, segmented panels, and mechanical arms are used to adjust jet nozzle effective area, then the jet nozzle effective area can be adjusted, but the device complexity increases

Engineering Contradiction:
Improvejet nozzle effective area adjustment capabilityVSAvoidmechanical system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical actuation systems with a simplified inflatable diaphragm system controlled by fluid pressure. This substitution eliminates multiple mechanical components (actuators, mechanical arms, pivot joints) and their associated linkages, significantly reducing device complexity while preserving the ability to adjust jet nozzle effective area.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and removes unnecessary mechanical intermediary components from the traditional actuation system. By eliminating mechanical arms, pivot joints, and multiple actuators, the design achieves jet nozzle area adjustment through a more direct and simpler inflatable diaphragm mechanism, reducing overall system complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If multiple actuators, segmented panels, and mechanical arms are used to adjust jet nozzle effective area, then the jet nozzle effective area can be adjusted, but the expense increases

Engineering Contradiction:
Improvejet nozzle effective area adjustment capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive mechanical actuation systems with a more cost-effective inflatable diaphragm system. By eliminating the need for multiple precision-machined mechanical components (actuators, mechanical arms, pivot joints), the design reduces manufacturing complexity and material costs while maintaining the required adaptability function.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses flexible inflatable diaphragms (thin films) instead of rigid mechanical components. These flexible membranes are generally less expensive to manufacture than precision mechanical parts, reducing overall system cost while providing the necessary function of controlling panel deployment to adjust jet nozzle effective area.

Inventive Principle:
Principle #30Flexible shells and thin films

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 provides a compact and efficient mechanism for adjusting the jet nozzle effective area, enhancing engine performance and efficiency by modulating the fluid pressure within inflatable diaphragms and hinged panels.

Implementation Method 1

increasing a fluid pressure in at least one inflatable diaphragm disposed at the jet nozzle

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Implementation Method 2

at least one inflatable diaphragm may be configured to expand into the jet nozzle when the fluid pressure within the at least one inflatable diaphragm is increased

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4707574A1Jet nozzle effective area control system for gas turbine engine
Publication Date: 2026.03.11 PRATT & WHITNEY CANADA CORP
  • EP4707574A1 patent drawingFigure 1A
  • EP4707574A1 patent drawingFigure 1B
  • EP4707574A1 patent drawingFigure 1C

AI summary

An aircraft gas turbine engine (200) includes a fan (205) that in operation moves air through both a core airflow path and a bypass airflow path of the gas turbine engine (200). The core airflow path and the bypass airflow path converge at a jet nozzle (210) of the gas turbine engine (200). A method of controlling the gas turbine engine (200) includes detecting, at a controller of the gas turbine engine (200), a cruise operating condition of the gas turbine engine (200), and in response to detecting the cruise operating condition, operating a mechanism of the gas turbine engine (200) to decrease an effective area of the jet nozzle (210).