Turbofan Grating With Segmented Fins To Reduce Flow Separation
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Solution Overview
Problem
The existing gratings for turbofan engines suffer from reduced performance due to air flow separation at the trailing edges of the fins, which affects the efficiency and weight of the grating in diverting secondary flows.
Innovation Solution
A grating design featuring two types of fins with curved profiles, where the second type has a smaller chord and optimized geometric parameters such as chord length, height, and angle configurations, inserted between the first type fins, to reduce weight and enhance diversion efficiency by minimizing flow separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fins with curved profiles are used to divert secondary flow, then flow diversion efficiency is improved, but air flow separation at trailing edges increases which reduces performance
Solution Approach 1:
The grating is divided into two types of fins with different chord lengths. First type fins have a larger chord and second type fins have a smaller cord, with each fin of one type inserted between two fins of the other type. This segmentation allows different regions of the grating to handle flow at different angles, reducing overall flow separation while maintaining diversion efficiency.
Solution Approach 2:
Different fin configurations are applied at different locations within the grating. The alternating pattern of first and second type fins creates local variations in flow interaction, with smaller chord fins in certain positions reducing flow separation in critical areas while larger chord fins provide sufficient diversion capability in other regions.
2Reliability
If fin cord is reduced to minimize flow separation, then performance is improved, but weight reduction is not sufficient
Solution Approach 1:
The grating uses a segmented fin structure with two types of fins having different cord lengths. By inserting smaller cord fins between larger cord fins, the overall weight is reduced while maintaining sufficient structural integrity and aerodynamic performance through the distributed pattern of fins throughout the grating assembly.
3Productivity
If alternating fin patterns are used to reduce flow separation, then aerodynamic efficiency is improved, but device complexity increases
Solution Approach 1:
The grating structure is segmented into two simple fin types that can be systematically arranged in an alternating pattern. This segmentation into basic repeating units simplifies manufacturing and assembly while achieving the aerodynamic benefits of the complex alternating pattern, as each fin type can be produced using standard processes and then assembled in the optimized sequence.
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 proposed grating design reduces weight while ensuring efficient diversion of secondary flows by minimizing drag and flow separation, thereby improving the overall performance of the turbofan engine's reverse flow system.
Implementation Method 1
the air flow at the output of the grating tends to separate at the trailing edge of each fin, which tends to reduce the performance of the grating
Data Source
AI summary
A grating for the formation of a reverse flow of a turbofan engine and comprising fins of a first type having a curved profile whose rounding is oriented aft and whose center of curvature is forward relative to the fin of the first type, fins of a second type having a curved profile whose rounding is oriented aft and whose center of curvature is forward relative to the fin of the second type. In this grating, each fin of one of the two types is inserted between two fins of the other type moving from forward to aft and the cord of the fins of the second type is smaller than the cord of the fins of the first type.