Variable-section nozzle flap alignment via radial offset
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional variable-section turbomachine nozzles with moving flaps experience leaks between adjacent flaps due to offset pivoting, leading to performance issues such as reduced thrust and increased specific consumption during operation.
Innovation Solution
Introducing a radial offset between moving flaps associated with follower and controlled levers, achieved by modifying the machining of follower levers, ensures that all flaps align on a common diameter during operation, preventing leaks and maintaining simplicity and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If moving flaps are actuated by control levers with swivel-fork connections, then the nozzle can modify the primary stream profile, but large leaks occur between adjacent flaps due to offset pivoting
Solution Approach 1:
The patent applies preliminary action by pre-setting a radial offset between follower flaps and controlled flaps when the nozzle is at rest. This offset is built into the initial configuration of the control levers and transmission links, so that when the nozzle operates, the flaps automatically align on a common diameter without requiring active compensation during operation.
Solution Approach 2:
The patent changes the geometric parameter of the control lever system by introducing a radial offset between the pivot points of controlled flaps and follower flaps. This parameter modification transforms the kinematic behavior of the mechanism, ensuring that the flaps converge to the same diameter during operation, thereby eliminating leakage paths.
2Object-generated harmful factors
If radial offset is introduced between follower and controlled flaps, then leakage is eliminated and flaps align on common diameter, but the machining complexity of control levers increases
Solution Approach 1:
The patent applies local quality by introducing the radial offset only to the follower levers while leaving the controlled levers unchanged. This localized modification means that only specific components (the follower levers and their associated transmission links) require altered machining, rather than redesigning the entire control system. The offset is implemented through modified pivot point positioning or adjusted link lengths in the follower lever assembly.
Data Source
AI summary
A variable-section turbomachine nozzle comprises a plurality of moving flaps, and a moving flap control system comprising control levers each associated with a respective moving flap, the control levers comprising both controlled levers that are actuated directly by actuators, and follower levers that are actuated by the controlled levers via transmission links. When the nozzle is at rest, the flaps associated with the follower levers present a radial offset relative to the flaps associated with the controlled levers.