Bypass Engine Confluence Plate Adjustment for Variable Gas Dilution
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Solution Overview
Problem
Turbomachine designs face challenges in achieving optimal thermodynamic performance across different flight regimes due to uncertainties in operating conditions, particularly in the confluence of primary and secondary streams, where the bypass ratio is influenced by the shape and position of the confluence plate, leading to inefficiencies in air intake and gas dilution.
Innovation Solution
A movable confluence plate and ferrule arrangement allows adjustment of the bypass ratio by varying the position of the confluence plate axially, using adjustment mechanisms such as pivoting pins and ball joints, enabling precise control of the inlet geometry and flow proportions of the secondary stream to optimize gas dilution and engine performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the confluence plate position is fixed, then the structure is simple and reliable, but the bypass ratio cannot be adjusted to optimize performance across different flight regimes
Solution Approach 1:
The confluence plate is made movable along the axial direction, transforming from a fixed structure to a dynamic one. This allows the bypass ratio to be adjusted according to different flight regimes, resolving the contradiction between adaptability and structural simplicity by introducing controlled mobility rather than complete redesign
Solution Approach 2:
The confluence plate is divided into a fixed portion and a movable portion, allowing independent adjustment of the bypass ratio while maintaining the structural integrity of the fixed parts. This segmentation enables partial adjustment capability without requiring the entire structure to be complex or movable
2Productivity
If the confluence plate position is adjusted to optimize gas pressures and flow rates, then engine performance improves, but the mechanism adds complexity and potential reliability issues
Solution Approach 1:
The movable confluence plate enables dynamic optimization of gas pressures and flow rates during flight, allowing the engine to adapt to different operating conditions. This dynamic adjustment improves productivity by optimizing performance across flight regimes while the simplicity of the sliding mechanism along the axial direction minimizes added complexity
Solution Approach 2:
By changing the axial position of the confluence plate, the bypass ratio parameter is adjusted to optimize engine performance. This parameter change allows the system to adapt to different flight regimes, improving thrust and fuel efficiency without requiring complex active control systems
3Manufacturing precision
If the confluence plate is made movable to vary inlet geometry, then flow control precision improves, but manufacturing and assembly complexity increases
Solution Approach 1:
The confluence plate is segmented into fixed and movable portions, allowing the movable part to be manufactured and assembled separately. This segmentation enables precise control of inlet geometry through the movable portion while keeping the fixed portion simple and easy to manufacture
Solution Approach 2:
The movable confluence plate provides dynamic control of inlet geometry, allowing precise adjustment of flow characteristics. The sliding mechanism along the axial direction maintains manufacturing simplicity by using straightforward linear motion rather than complex multi-axis positioning
Data Source
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AI summary
The invention relates to a confluence structure of an aircraft bypass turbine engine which comprises a confluence plate (13) with a downstream end (16) supported by a portion (20) that is movable in the direction of the axis (X) by a control mechanism (26 to 32) which can optionally be adjusted in flight. A mobile portion (22) of a sleeve (18) delimiting the secondary stream (10) on the outside, and an inner projection (25) of the outer casing (11) can also slide axially in certain embodiments. This provides a wide range of options for modifying the gas dilution and operating conditions of the engine.