Turbofan Nacelle Reverser Flap Coordinated Actuation
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Solution Overview
Problem
Existing turbofan nacelle reverser flap mechanisms are limited in their opening mechanisms, seeking alternative methods to improve airflow management and reduce noise.
Innovation Solution
A nacelle design featuring a fixed and mobile cowl with a reverser flap that translates and rotates, coordinated by a drive mechanism, along with an additional flap that extends to divert secondary flow, enhancing airflow diversion and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional reverser flap mechanism is used, then the structure is simple, but the airflow diversion capability is limited
Solution Approach 1:
The reverser flap system is divided into multiple independent flaps (first reverser flap and second reverser flap) that can be controlled separately. Each flap can be positioned independently to optimize airflow diversion for different operating conditions, thereby enhancing adaptability without requiring a single complex mechanism to handle all scenarios.
Solution Approach 2:
The reverser flaps are designed to be mobile rather than fixed, allowing dynamic adjustment of their positions. The mobile cowl and rotatable flaps can adapt to varying flight conditions, enabling the system to optimize airflow diversion in real-time, thus improving versatility while maintaining manageable complexity through modular actuation.
2Productivity
If the reverser flap is kept in closed position, then the nacelle surface remains continuous, but secondary flow cannot be expelled
Solution Approach 1:
The reverser flaps and mobile cowl are designed as dynamic components that can change position based on operational requirements. When secondary flow expulsion is needed, the flaps rotate open and the cowl moves aft, creating controlled openings in the nacelle surface. This dynamic capability allows the system to maintain surface continuity during normal operation while enabling efficient flow expulsion when required.
Solution Approach 2:
The system changes the geometric parameters of the nacelle surface by rotating the flaps and moving the cowl. The opening angle of the flaps and the position of the mobile cowl can be adjusted to control the size and shape of the openings, thereby optimizing secondary flow expulsion efficiency while minimizing disruption to nacelle surface continuity when closed.
3Adaptability or versatility
If the mobile cowl is moved aft to open the window, then airflow diversion is improved, but the sealing capability is reduced
Solution Approach 1:
The mobile cowl and reverser flaps incorporate sealing elements that can flex and adapt to maintain tight seals when the components are in their closed positions. These flexible sealing mechanisms ensure that the nacelle maintains its aerodynamic integrity and prevents leakage when the flaps are retracted and the cowl is in the forward position, thereby preserving sealing capability while enabling airflow diversion when needed.
Data Source
AI summary
A nacelle has a fixed cowl and a mobile cowl, which is movable along a translation path between closing and opening positions, a window delimited by the fixed cowl and the mobile cowl and open between an airflow and exterior of the nacelle, a reverser flap rotatably mounted to move between closed and open positions, and a drive mechanism configured to control passage of the reverser flap between the closed and open positions as the mobile cowl moves between the closed and open positions. From the closing/closed positions, the drive mechanism assures a translation of the mobile cowl and a rotation of the reverser flap toward their respective opening/open positions. From the open/opening positions, the drive mechanism assures a rotation of the reverser flap and a translation of the mobile cowl toward their respective closed/closing position. In some embodiments, the nacelle further includes an additional, or second, flap.