Swirl De-Icing Injector for Turbojet Nacelle Air Intake Mixing
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Solution Overview
Problem
Existing de-icing systems for aircraft turbojet nacelles suffer from low energy efficiency and complex maintenance due to non-homogeneous mixing of hot and fresh air flows, leading to hot spots and reduced service life, and require large injectors that are difficult to remove for maintenance.
Innovation Solution
A de-icing injector with a peripheral member that includes a peripheral mouth and inner guide wall, featuring rotating members to twist and accelerate the hot air flow, promoting concentric mixing with fresh air, and maintaining a small diameter for easy maintenance access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional cylindrical injector is used to inject hot air flow, then the structure is simple, but the energy efficiency is low due to non-homogeneous mixing with fresh air flow
Solution Approach 1:
The injector employs rotating members that rotate the hot air flow during injection, transforming the static flow into a dynamic swirling flow. This rotation promotes better mixing with the fresh air flow, improving energy efficiency while the compact design keeps the overall structure manageable.
Solution Approach 2:
The rotating members create turbulence and chaotic motion in the hot air flow, effectively mixing it with the fresh air flow. This mechanical mixing action ensures homogeneous temperature distribution and prevents hot spots, resolving the energy efficiency issue.
2Reliability
If an injector with a large peripheral member is used to improve mixing, then the mixing performance is high, but the installation becomes complex and maintenance becomes difficult
Solution Approach 1:
The rotating members are nested within the peripheral member, allowing the injector to maintain a compact overall dimension. The rotating members are positioned inside the peripheral member's passage duct, enabling effective mixing without requiring a large external diameter that would complicate maintenance.
Solution Approach 2:
The injector is divided into functional segments: the peripheral member for structural support and flow guidance, and the rotating members for mixing. This segmentation allows the rotating members to be accessed or replaced independently while maintaining the compact form factor needed for easy maintenance.
3Ease of repair
If the peripheral member diameter is reduced for easy maintenance, then maintenance accessibility improves, but the mixing capacity between hot and fresh air flows is reduced
Solution Approach 1:
The rotating members compensate for the reduced diameter by introducing dynamic motion to the air flows. The rotation creates centrifugal forces and turbulence that enhance mixing efficiency, allowing adequate mixing capacity even with a compact diameter that facilitates maintenance.
Solution Approach 2:
The system changes the flow parameters by introducing rotation and turbulence through the rotating members. This transforms the flow from a simple laminar flow to a turbulent swirling flow, improving mixing efficiency per unit volume and compensating for the reduced diameter.
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 system achieves optimal temperature and flow rate mixing, reducing hot spots and extending service life while allowing easy maintenance through a compact design.
Implementation Method 1
it is known to circulate a hot air flow FAC in the inner cavity 204 in order to heat the inner wall 201 by thermal convection and thus avoid the build-up of ice
Implementation Method 2
The use of rotating members also promotes mixing by forming turbulence at the interface between the hot air flow and the fresh air flow
Implementation Method 3
The inner guide wall helps to create a negative pressure area upstream of the passage duct in order to accelerate the fresh air flow from upstream to downstream
Data Source
AI summary
An injector for a de-icing device for an air intake of an aircraft turbojet nacelle. The injector including a peripheral member internally defining a passage duct. The peripheral member including a peripheral mouth configured to inject a peripheral hot air flow so as to circulate a flow of fresh air in the passage duct from upstream to downstream. The peripheral member including an inner guide wall located downstream of the peripheral mouth. The peripheral member including a plurality of members for rotating the hot air flow during the injection thereof.