Dimpled Stator Strut Geometry for Lower Gas Turbine Pressure Drop
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Solution Overview
Problem
Current gas turbine engine stator cases with struts face challenges in efficiently guiding exhaust flow and minimizing pressure drop, which affects overall engine performance.
Innovation Solution
A stator case design featuring an outer ring and inner ring supported by circumferentially spaced struts, with airfoil sections and strategically placed dimples on the struts to introduce turbulence and reduce flow separation, thereby minimizing pressure drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If smooth strut surfaces are used in the stator case, then manufacturing is simpler, but flow separation occurs and pressure drop increases
Solution Approach 1:
The strut surface is modified with dimples only in specific locations (leading portion and/or trailing portion) rather than being uniformly smooth or uniformly textured. This local modification creates turbulence in critical flow regions to prevent separation, while maintaining manufacturing simplicity elsewhere.
Solution Approach 2:
Instead of making the entire strut surface rough or textured, only partial regions (leading and/or trailing portions) are provided with dimples. This partial action is sufficient to generate the needed turbulence and prevent flow separation without requiring complete surface modification.
2Loss of energy
If strut surfaces are modified to reduce flow separation, then pressure drop decreases, but manufacturing complexity increases
Solution Approach 1:
The complex dimpled surface geometry is applied only to specific portions (leading and/or trailing portions) of the strut rather than the entire surface. This localized complexity achieves the flow control benefit while minimizing the overall manufacturing complexity.
Solution Approach 2:
The dimple modification is applied partially to only certain regions of the strut surface that are most critical for flow separation prevention. This partial modification achieves the desired pressure drop reduction without requiring complete surface complexification.
3Loss of energy
If dimples are placed on strut leading portions, then turbulence is introduced and flow separation is reduced, but manufacturing precision requirements increase
Solution Approach 1:
Dimples are concentrated in the leading portion (and/or trailing portion) of the strut where they are most effective at preventing flow separation. This localized placement focuses the manufacturing precision requirements to specific critical regions rather than distributing them across the entire strut surface.
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 design effectively guides exhaust flow and reduces pressure drop, enhancing the performance of gas turbine engines by maintaining a turbulent boundary layer and minimizing flow separation.
Implementation Method 1
dimples on the struts to introduce turbulence and reduce flow separation
Implementation Method 2
dimples on the struts to introduce turbulence and reduce flow separation
Data Source
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AI summary
A strut (66) for a gas turbine engine includes an airfoil section (67) extending in a spanwise direction (R) between a first platform (64P) and a second platform (62P), extending in a chordwise direction (C) between a leading edge (82) and trailing edge to define a chord length, and extending in a thickness direction (T) between a first side and a second side to define a chord width. Exterior surfaces of the airfoil section (67) define a leading portion (68) between the leading edge (82) and a widest location of the airfoil section (67) relative to the thickness direction (T), and a trailing portion (70) between the widest location and the trailing edge. The exterior surfaces establish a respective exterior contour for each span position between a 0% span position and a 100% span position. The exterior surfaces define a plurality of dimples (72) in the leading portion (68).