Composite Outflow Valve Structure for Aircraft Thrust Recovery
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Solution Overview
Problem
Thrust recovery valves in aircraft cabin pressure control systems are heavy and complex due to large swing arms and robust materials, which hinder the use of lightweight materials for valve door elements with complex shapes.
Innovation Solution
The design incorporates composite materials for the valve elements, including side caps, an end cap, and a shell, with female anti-rotation features and a carbon-fiber reinforced resin matrix, eliminating the need for large swing arms and optimizing the shape for thrust recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If robust materials and large swing arms are used in thrust recovery valves, then strength and reliability are improved, but weight and device complexity increase
Solution Approach 1:
The valve door element is constructed using composite materials, specifically a foam core (such as Rohacell) surrounded by a composite shell. This composite structure provides the necessary strength and rigidity to withstand aerodynamic loads and pressure differential forces while significantly reducing the weight compared to traditional solid metal constructions. The composite materials allow the valve to maintain structural integrity without requiring large swing arms for mechanical advantage.
2Productivity
If complex shapes are used for valve door elements to optimize thrust, then thrust recovery performance is improved, but manufacturing complexity and weight increase
Solution Approach 1:
The valve door element is segmented into distinct functional components: a foam core providing structural support and a separate composite shell forming the aerodynamic surface. This segmentation allows the complex aerodynamic shape to be achieved through the shell while the core provides simplified structural support, reducing overall manufacturing complexity.
Solution Approach 2:
The foam core is nested within the composite shell, creating a layered structure where the inner core provides structural integrity and the outer shell provides the complex aerodynamic shape. This nesting approach allows complex external geometry to be achieved without proportionally increasing internal structural complexity or weight.
3Reliability
If large swing arms are used to provide mechanical advantage, then valve operation reliability is improved, but device complexity and weight increase
Solution Approach 1:
The patent replaces the traditional mechanical swing arm system with direct actuation of the composite valve door element. The actuator connects directly to the valve door, eliminating the need for intermediate swing arms and their associated complex linkages. This substitution maintains reliable valve operation while significantly reducing mechanical complexity and weight.
Data Source
AI summary
An aircraft cabin pressure control system outflow thrust recovery valve includes a frame, a valve element, and actuation hardware. The frame, valve element, and at least a portion of the actuation hardware are made of composite material. The actuation hardware is disposed external to the frame.