Segmented Multi-Lobe Exhaust Mixer for Turbofan Engines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing metal exhaust mixers in turbofan engines are heavy and not suitable for thermal gradients, necessitating a lighter, thermally stable material solution for improved manufacturability and performance.
Innovation Solution
A multi-lobe exhaust mixer design using segmented lobe segments made of thermally stable materials like ceramic matrix composites, with alternating inner and outer lobes that overlap radially, allowing for modular construction and vibration damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal exhaust mixers are used, then structural strength is ensured, but weight increases and thermal gradient resistance decreases
Solution Approach 1:
The exhaust mixer is divided into multiple individual lobe segments that can be manufactured separately and assembled together. Each segment can be optimized for strength while reducing overall weight, and the segmented structure allows for thermal expansion without compromising structural integrity.
Solution Approach 2:
The patent enables the use of different materials for different lobe segments, including lightweight materials and thermal gradient resistant materials such as ceramic matrix composites (CMC). This allows optimization of each segment's material properties according to its specific functional requirements, reducing overall weight while maintaining structural strength and thermal resistance.
2Strength
If metal exhaust mixers are used, then structural strength is ensured, but thermal gradient resistance decreases
Solution Approach 1:
The patent specifically enables the use of thermal gradient resistant materials such as ceramic matrix composites (CMC) for lobe segments exposed to high thermal gradients. These materials maintain structural strength while resisting thermal stress and gradient effects that would compromise metal structures.
Solution Approach 2:
By segmenting the exhaust mixer, each individual lobe segment can be designed with material properties optimized for its specific thermal environment. This allows the use of advanced materials like CMC in high-temperature zones while using lighter materials in cooler zones, overall improving thermal gradient resistance while maintaining structural integrity.
3Device complexity
If segmented lobe segments are used, then manufacturing complexity increases, but ease of manufacture improves
Solution Approach 1:
The exhaust mixer is divided into multiple individual lobe segments that can be manufactured using standard casting or molding processes independently, then assembled together. This segmentation allows each component to be produced with simpler, more cost-effective manufacturing methods compared to producing a single complex metal structure, while the modular assembly maintains structural integrity.
Data Source
AI summary
A multi-lobe exhaust mixer has an annular body composed of a plurality of circumferentially adjacent lobe segments. The lobe segments may be made of a ceramic matrix composite material to reduce the weight of the mixer and ensure proper behavior when exposed to high thermal gradients. Each lobe segment may have partial lobes at circumferentially opposed ends thereof and at least one complete lobe therebetween. The partial lobes of the circumferentially adjacent lobe segments combining to conjointly form complete lobes at the junction between the circumferentially adjacent lobe segments. The partial lobes may be nested into each other to dampen vibrations.