Variable Geometry Inlet Guide Vane Flow Control
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Solution Overview
Problem
Existing gas turbine engine inlet guide vanes experience airflow separation and turbulence, particularly at high incidence angles, leading to increased wear on downstream components due to inadequate design consideration for the deflected position, resulting in inefficient flow and high losses.
Innovation Solution
The design of the inlet guide vane includes a strut with continuously curved side surfaces and a flap with pressure and suction side surfaces having peaks spaced away from the leading edge, ensuring low momentum air is energized and attached to the flap, preventing flow separation and optimizing airflow at various incidence angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the inlet guide vane is optimized for the zero deflection position, then the performance at high speeds is improved, but the airflow separation and turbulence occur at the deflected position
Solution Approach 1:
The patent applies different geometric characteristics to different regions of the flap. The suction side surface has a peak spaced further from the leading edge compared to the pressure side surface peak, creating localized flow control zones. This allows the flap to maintain attached flow at deflected positions while preserving performance at zero deflection, resolving the contradiction between high-speed efficiency and flow stability.
Solution Approach 2:
The patent designs the flap geometry to dynamically adapt its flow characteristics based on the deflection angle. The asymmetric peak positioning allows the flow attachment behavior to change favorably as the flap deflects, maintaining performance across the full range of motion rather than being optimized for a single static position.
2Ease of operation
If there is a gap between the trailing edge of the strut and the leading edge of the flap, then the flap can pivot freely, but the air flow loses momentum and becomes disrupted
Solution Approach 1:
The patent introduces a carefully designed gap region that acts as an intermediary between the strut and flap. The specific positioning of the flap's leading edge relative to the strut's trailing edge, combined with the asymmetric peak geometry, creates a flow path that maintains momentum through the gap region rather than allowing complete flow disruption.
Solution Approach 2:
The patent modifies the geometric parameters of the flap surfaces, specifically the spacing of the peaks from the leading edge on each side. This parameter optimization ensures that the flow re-energizes appropriately after passing through the gap, maintaining attachment to the flap surface while preserving pivotability.
3Manufacturing precision
If the flap has camber that varies along its span, then the exit turning angle can be optimized for zero deflection position, but flow separation occurs at high incidence angles
Solution Approach 1:
The patent applies asymmetric camber distribution with peaks positioned at different distances from the leading edge on the pressure and suction sides. This localized geometric variation optimizes the exit turning angle distribution while preventing flow separation at high incidence angles, resolving the contradiction between precision angle control and flow attachment reliability.
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
This design maintains attached airflow and reduces turbulence, enhancing the flow quality and minimizing wear on engine components across different operational positions, thereby improving the overall efficiency and reliability of the gas turbine engine.
Implementation Method 1
low momentum air in the gap between the strut and the flap will be energized and entrained in the boundary layer of the flap
Implementation Method 2
the known inlet guide vanes may cause separation of the air flow from the flap
Implementation Method 3
low momentum air in the gap between the strut and the flap will be energized and entrained in the boundary layer of the flap
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
An inlet guide vane (30) provides improved, smooth airflow and avoids separation of flow even at high incidence angles. The inlet guide vane (30) includes a strut (32) having opposite side surfaces (46,48) that are continuously curved to provide a controlled velocity distribution at the trailing edge (44) of the strut (32). The inlet guide vane (30) further includes a flap (34) having a leading edge (52) aligned behind the trailing edge (44) of the strut (32). Generally, the strut (32) and the flap (34) are designed together so that low momentum air in the gap (59) between the strut (32) and the flap (34) will be energized and entrained in the boundary layer of the flap (34). The airflow from the gap (59) will remain attached to the flap (34) to improve the flow from the flap (34).