Bistable Vortex Generator for Aircraft Hot-Air Exhaust Cooling
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Solution Overview
Problem
Aircraft hot-air exhaust outlets pose a challenge due to the need for heavy, temperature-resistant materials to handle high temperatures, which increases weight and reduces fuel economy, as existing vortex generators either require constant operation or are not adaptable to varying flight conditions.
Innovation Solution
A bistable laminate vortex generator that snaps between active and inactive states, using a thermal expansion member to adjust its flow surface orientation based on temperature, allowing it to interrupt or minimize hot-air exhaust flow as needed, promoting airflow mixing or separation depending on flight stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat shields or titanium components are used to protect against hot-air exhaust, then temperature resistance is improved, but weight increases and fuel economy deteriorates
Solution Approach 1:
The invention extracts and removes the heat shield component entirely from the exhaust system. Instead of protecting components from hot air, the vortex generator actively mixes the hot exhaust air with cooler ambient air, eliminating the need for thermal protection measures and allowing the use of standard lightweight materials.
Solution Approach 2:
The invention converts the harmful hot exhaust air into a beneficial cooling resource. By inducing vortex flow that mixes hot exhaust air with cooler ambient air, the system uses the previously harmful thermal energy to actively cool the exhaust, thereby protecting components without requiring additional shielding.
2Temperature
If vortex generators are constantly operated to cool exhaust flow, then cooling effect is improved, but energy consumption increases
Solution Approach 1:
The vortex generator is designed with movable vanes that can dynamically adjust their angle and position based on flight conditions. This dynamic adaptability allows the system to optimize cooling performance only when necessary, reducing energy consumption during cruise while maintaining effective cooling during take-off and landing phases.
Solution Approach 2:
The system changes operational parameters (vane angle, flow direction) based on flight stage requirements. During cruise, parameters are adjusted to minimize interference and energy use, while during take-off and landing, parameters are optimized for maximum cooling effect, thereby reducing overall energy consumption.
3Temperature
If vortex generators are designed for high temperature environments, then temperature resistance is improved, but device complexity increases
Solution Approach 1:
The invention removes the requirement for high-temperature-resistant materials and specialized components by eliminating direct exposure to hot exhaust gases. The vortex generator mixes hot air with cool air upstream, protecting all components from thermal damage and allowing the use of standard lightweight materials throughout the system.
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
Enables the use of lower-temperature-rated materials, reduces the need for heat shields, and optimizes fuel efficiency by actuating only when necessary, enhancing cooling during take-off and landing while minimizing interference during cruise.
Implementation Method 1
The thermal expansion member, such as a metallic strip. The thermal expansion member may be a bimetallic strip. The thermal expansion member is configured to act on the bistable laminate in dependence on a temperature variations to impart a mechanical displacement.
Implementation Method 2
the at least part of the flow surface is configured to interrupt the hot-air exhaust flow and generate a flow vortex to cool the air flow over the assembly surface
Implementation Method 3
generate a flow vortex to cool the air flow over the assembly surface
Implementation Method 4
The temperature actuated member comprises a bistable laminate arranged to snap between two stable states. An advantage of using a bistable laminate is that the vortex generator is able to snap between two fixed states without an intermediate state
Data Source
Figure 1~2
Figure 3A~4B
Figure 5A~5C
AI summary
The present application relates to a vortex generator (20). The present application also relates to an aircraft assembly with a hot air exhaust outlet (15). The aircraft assembly has an assembly surface over which a hot-air exhaust flow from the hot-air exhaust outlet (15) is exhausted. The aircraft assembly also has a vortex generator (20) with a flow surface (27, 28). The flow surface (27, 28) lies in an air flow over the vortex generator (20). The flow surface (27, 28) is arranged to interrupt the hot-air exhaust flow and generates a flow vortex to cool the air flow over the assembly surface.