Aircraft Turbine Compartment Ventilation with Passive Shape Memory Alloy Flap
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Solution Overview
Problem
Existing ventilation systems for aircraft turbine engines generate drag, impairing performance during flight, especially in cruising phases, due to their design, and require active electrical or hydraulic systems which are complex to implement.
Innovation Solution
A deployable-retractable ventilation assembly with a passive operation system using a shape memory alloy spring and a Z-shaped flap to automatically control airflow, minimizing drag and eliminating the need for external actuation systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a scoop is used to take in cold air for compartment ventilation, then the compartment temperature remains below the limit temperature, but the scoop generates drag which impairs aircraft performance in flight
Solution Approach 1:
The ventilation opening is made dynamic through a deployable-retractable assembly that can adjust its state based on operational requirements. The assembly includes a flap that can be positioned to open or close the ventilation opening, allowing the system to adapt between ventilation mode (ground operation) and aerodynamic mode (flight), thereby resolving the contradiction between temperature control and drag reduction
Solution Approach 2:
The system changes the physical state of the ventilation opening from open to closed by deploying or retracting the assembly. This parameter change allows the same structure to serve different functions: when deployed, it provides full ventilation; when retracted, it minimizes drag while maintaining adequate ventilation through the flap design
2Ease of operation
If an active electrical or hydraulic system is used to control the ventilation assembly, then precise control of ventilation is achieved, but the system becomes complex to implement
Solution Approach 1:
The ventilation assembly is designed to be self-actuating through passive thermal expansion mechanisms. The bimetallic strip or shape memory alloy spring automatically responds to temperature changes within the compartment, deploying the ventilation assembly when overheating is detected and retracting it when temperature normalizes, eliminating the need for external electrical or hydraulic control systems
Solution Approach 2:
The patent replaces complex electrical or hydraulic actuation systems with a passive thermal-mechanical system. The bimetallic strip or shape memory alloy directly converts thermal energy into mechanical motion to actuate the flap, substituting sophisticated control systems with a simple, reliable thermal response mechanism
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 effectively cools heat-sensitive components while maintaining aircraft performance by automatically adjusting ventilation based on temperature needs, reducing drag and simplifying implementation with a passive, non-electrical or hydraulic system.
Implementation Method 1
a passive operation system using a shape memory alloy spring and a Z-shaped flap to automatically control airflow
Data Source
Figure 1
Figure 2a~2c
Figure 3a~3c
AI summary
The invention relates to a double-flow turbomachine comprising a nacelle defining a blower duct (30) with an intervein, the turbomachine comprising at least one compartment (40) made in the thickness of the intervein or the nacelle (3), said compartment being separated from the blower duct (30) by a cold wall (7b, 3b) and comprising at least one temperature-sensitive element, the compartment (40) being further equipped with a ventilation assembly (50) comprising at least one ventilation opening (51) made in the cold wall (7b, 3b) for drawing air (F1) from the blower duct (30) into the compartment (40) during operation, each ventilation opening (51) comprising a passive opening system (60) disposed in the compartment (40),said system comprising a shutter (61) movable between an open position in which the shutter (61) releases said opening (51) and a closed position in which the shutter (61) closes said opening (51), and a passive actuation device (62) for the shutter (61) to move the shutter between the two positions.