Aircraft Exhaust Mixer Vane Segmentation for Plume Reduction
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Solution Overview
Problem
Conventional exhaust mixers on aircraft are inefficient in reducing the size of hot exhaust plumes and infrared signatures, as they do not effectively distribute the flow to achieve optimal mixing and plume reduction.
Innovation Solution
The design features a plurality of outwardly and inwardly oriented vanes with planar surfaces, creating a core flow area where a minority of the total flow travels, facilitating efficient mixing by distributing flow through both core and non-core areas, with planar surfaces simplifying fabrication and attachment, and optimizing angles and fillet radii for enhanced mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional exhaust mixer configurations are used, then the structure is simple and easy to manufacture, but the mixing efficiency is poor and the thermal plume length is not sufficiently reduced
Solution Approach 1:
The exhaust mixer is segmented into multiple vanes (at least three vanes) that divide the exhaust flow into multiple separate streams. Each vane creates individual flow paths that are subsequently mixed with cooling air, improving mixing efficiency while maintaining a manageable structural complexity through modular segmentation of the flow.
Solution Approach 2:
Different regions of the exhaust mixer are designed with different vane orientations and configurations. The vanes are positioned at specific angles relative to the exhaust flow direction, with some vanes having leading edges oriented at different angles to optimize local flow distribution and mixing characteristics in different zones of the mixer.
2Productivity
If flow is distributed evenly through all areas, then mixing is simplified, but the core flow area should contain only a minority of total flow for optimal mixing performance
Solution Approach 1:
The vane configurations and orientations are specifically designed to change the flow distribution parameters, directing the majority of the flow (more than 50%) through the non-core areas surrounding the core flow area. This parameter optimization ensures that only a minority of total flow passes through the core flow area, achieving optimal mixing efficiency as specified in the invention.
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 configuration results in a 40-50% reduction in thermal plume length, minimizing infrared signatures and improving pressure loss performance compared to conventional mixers.
Implementation Method 1
Exhaust mixers are commonly employed on aircraft to cool hot exhaust gases by mixing them with cooler gases that flow around the exhaust mixer
Data Source
AI summary
An exhaust mixer includes, a plurality of outwardly oriented vanes having planar surfaces, and a plurality of inwardly oriented vanes alternately positioned perimetrically between the plurality of outwardly oriented vanes, and a core flow area defined inwardly of inner most portions of the plurality of inwardly oriented vanes, the exhaust mixer being configured such that a minority of the total flow through the exhaust mixer travels through the core flow area when the exhaust mixer is employed during a mixing operation.