Jet Engine Radially Variable Wall for Flow Control

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Solution Overview

Problem

Existing jet engine designs with variable nozzles are heavy, complex, and inefficient due to steps and gaps between individual parts, limiting the ability to achieve high efficiency, especially in supersonic engines.

Innovation Solution

A jet engine with a flow duct featuring a radially variable wall having a wave-like structure with convex and concave areas, connected by a connection structure with adjustment units, allowing for precise adjustment of the flow cross-section at defined control sections, eliminating steps and gaps for improved efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a circumferential wall is constructed with many individual parts that can be displaced relative to each other, then the flow cross-section can be varied, but the wall and mechanisms become heavy and complex

Engineering Contradiction:
Improveflow cross-section variabilityVSAvoidwall and mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies a flexible membrane structure with wave-like corrugations that can deform radially to vary the flow cross-section. This continuous flexible surface replaces the traditional assembly of discrete movable wall segments, eliminating the need for complex mechanical displacement mechanisms while maintaining adaptability. The membrane's inherent flexibility allows it to assume different radial positions to control flow area.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention introduces an adjustment device with actuating elements that dynamically control the radial position of the flexible membrane at different circumferential locations. This dynamic adjustment capability allows the flow cross-section to be varied on-demand, transforming the static wall structure into an adaptive system that responds to operational requirements without permanent mechanical linkages.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a circumferential wall is constructed with many individual parts that can be displaced relative to each other, then the flow cross-section can be varied, but steps and gaps exist between individual wall components leading to efficiency losses

Engineering Contradiction:
Improveflow cross-section variabilityVSAvoidefficiency losses due to steps and gaps
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The continuous flexible membrane eliminates gaps and steps between discrete components by providing an unbroken surface that deforms uniformly. This continuous structure prevents flow separation and turbulence that would occur at interfaces between separate wall segments, thereby reducing energy losses while maintaining the ability to vary flow cross-section.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention merges multiple discrete wall segments into a single continuous flexible membrane structure. This unification eliminates the interfaces between components where steps and gaps would create flow disturbances, combining the functions of multiple parts into one seamless element that maintains flow continuity.

Inventive Principle:
Principle #5Merging (Combining)

3Weight of moving object

If a radially variable wall with wave-like structure is used, then the design is lightweight and cost-effective, but precise adjustment of flow cross-section must be achieved

Engineering Contradiction:
Improvewall weightVSAvoidflow cross-section adjustment precision
Core Design Contradiction:
Weight of moving objectVSManufacturing precision

Solution Approach 1:

The adjustment device employs multiple independently controllable actuating elements that can be positioned dynamically to achieve precise radial displacement of the flexible membrane at specific circumferential locations. This dynamic control system allows fine-tuning of the flow cross-section by adjusting the position and force applied by each actuator, enabling precise control despite the lightweight flexible construction.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The adjustment mechanism is segmented into multiple independent actuating elements distributed around the circumference, each capable of independent control. This segmentation allows precise local adjustment of the membrane position, enabling accurate control of the flow cross-section profile by activating specific actuators with controlled force and displacement.

Inventive Principle:
Principle #1Segmentation

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 enables a high degree of efficiency by allowing precise adaptation of the flow cross-section to operating conditions, reducing material loading and turbulence, and extending the service life of the variable wall while maintaining a lightweight and cost-effective design.

Implementation Method 1

a radially variable wall having a wave-like structure with convex and concave areas... elastically designed, radially variable wall

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3585994B1Jet engine with a radially variable wall
Publication Date: 2022.04.06 ROLLS ROYCE DEUT LTD & CO KG
  • EP3585994B1 patent drawingFigure 1
  • EP3585994B1 patent drawingFigure 2~4
  • EP3585994B1 patent drawingFigure 5~6

AI summary

The invention relates to a jet engine (10) comprising a flow channel (36) which is located in a nacelle (15) and is delimited radially inside by a centerbody (44) and radially outside by an outer jet wall (45). The free cross-section of the flow channel (36) can be varied by an elastic, radially variable wall (46) of at least one of said structural components (44). The radially variable wall (46) has at least in part an at least approximately undulated structure (50) and is connected to an adjustment device (58) having an adjustment unit (54, 56). The variable wall (46) of one of the structural components (44) can be varied in the radial direction (R) in two defined control sections (60, 62) at least one of which defines an axial wall end (64) of the radially variable wall (46).